- Superb display
- Packed with activity tracking features
- Still great value for money
- Heart rate tracking is inconsistent
- Lacking smartwatch features
- Not a huge upgrade on GTS 3
The competition in the mid-range smartwatch field may be growing fiercer with every passing year, but Zepp Health's Amazfit is still managing to hold its own. And its latest entry, the GTS 4, promises plenty for a relatively low asking price.
Though it's not remarkably different from its predecessor on paper, additions like a built-in speaker, support for music downloads and dual-band GPS tracking do make this a generation that's intriguing - whether you're a newcomer to Amazfit or you're looking to upgrade.
With a slightly bumped price, however, it's now also in a heat alongside watches like the last-gen Samsung Galaxy Watch 4 and recently released Fitbit Versa 4. This makes it a more difficult sell than the GTS 3 - and a very big price difference away from its budget twin, the Amazfit Bip 3 Pro.
We've been testing out the GTS 4 - here's what we've made of its design, tracking accuracy, smartwatch features and battery life.
If you were to place the GTS 4 alongside its 2021 sibling, the GTS 3, we daresay you wouldn't be able to spot the difference.
It features the same 1.75-inch AMOLED color touchscreen, as well as the identical 390 x 450-pixel resolution, tempered glass covering and anti-fingerprint coating.
It's not very inspiring to have pretty much exactly the same 42mm case sitting on the wrist, but, on the other hand, there was nothing really missing from the GTS 3's design.
The case dimensions sit right in the middle for most users, meaning Amazfit just about gets away with only offering one size, and it's also extremely light, which ensures it never feels cumbersome on the wrist.
It is a little thicker than the GTS 3, but, again, you're very unlikely to notice. And given that this is likely due to Amazfit packing in a new microphone and speaker, it's understandable.
If we have a gripe with the design, it's that the build quality is still a little cheap-feeling. It's natural to expect some fall-off from the flagship smartwatches on the market, but this still doesn't necessarily feel like a mid-range device.
Still, this only really applies to elements like the crown, case and band, because the display is about as good as you'll find on any device. It can get seriously punchy if you max the settings out, and we've found it to be very responsive to both touch and wrist raises - much more so than we've found with Fitbit's latest smartwatches, for example.
No matter whether you have small or large wrists, we don't think this is a design that looks out of place. And it's very functional whether you're wearing it during exercise or sleep - and even if you wear it with a couple of sleeves.
At least to the untrained eye, it often just looks as if you're wearing Apple Watch, which is no bad thing, really.
While it may look like a bit of an Apple Watch clone, however, the Amazfit GTS 4 doesn't offer anything close to the kind of smartwatch experience you would receive on some like-priced devices.
We'll start here with the improvements, though. With the built-in speaker and microphone, things like Bluetooth calls are now possible and work well, while Amazon's Alexa can now read out answers aloud.
Music files can also finally be downloaded onto the watch, which is great for those who don't want to take their phone out during exercise, for example.
But, still, even the improved parts of the GTS 4 all have an underwhelming backdrop; while it's good that they're now here, they're also features that have been available for several years on other smartwatches, fitness trackers or sports watches.
In that sense, it's hard to really give Amazfit credit. And that's compounded by some other basics being completely absent, like NFC payments, though you do at least get the ability to add QR codes to your watch through the Zepp app.
This companion app is also where you go to download more apps to help bolster the experience. Except for the fact, well, there are no third-party apps on the Zepp store - only more of the company's own options that don't come pre-installed.
This is a real letdown and can make the experience feel pretty barebones at times, but, for its faults, Zepp does at least have a superb library of in-house watch faces for you to play around with on the GTS 4.
This makes it feel a bit more like a proper experience, but we'd caution anybody looking for a true smartwatch here. Almost all the traditional smartwatch elements are basic or a little buggy, and this means the GTS 4 is actually much more geared to life as a tracker.
When it comes to the real strength of the GTS 4, it's actually in the tracking. There's an entire wealth of tracked metrics to dive into - and a lot of it, really, appears to be inspired by Garmin.
In fact, testing the GTS 4 against our daily driver, the Garmin Forerunner 955 Solar, the experience and results were actually very comparable. This was especially obvious with things like Training Effect, as shown above, which is delivered after every workout, giving you a good look at the individual load and how the workout improved both your aerobic and anaerobic systems.
There are other premium metrics for runners, too, with the app delivering insights into the likes of gradient distribution, cadence, stride length, VO2 Max and EPOC.
It's not just during exercise in which the GTS 4 tracking experience is full, either. Sleep monitoring is pretty accurate, matching up relatively closely in each sleep stage and breathing rate to our Google Pixel Watch, while there is also a decent chunk of health metrics to tap into.
On-the-spot blood oxygen readings matched up to our Garmin, as did resting heart rate estimates, roughly, from each day.
We also really like how Zepp presents data like this in the app. Instead of just providing you with a cold hard figure, it couples it with a label.
Your resting heart rate might be described as 'Low', while your blood oxygen levels show as 'Normal' and stress levels as 'Relaxed'. It really drives home the idea these are 'live' readings - and it's much better and actionable info than we see in most companion apps.
We're less enthusiastic about PAI, a study-developed fitness metric Zepp uses to crystalize the key bits of data from your day. It's not that it's without merit, but it does require you to read up a fair bit on how it actually works in order to get a grasp of how it can be relevant to you.
GPS accuracy testing
With the new dual-band GPS support, the GTS 4 promises much more accurate tracking than what's come before. And, for the most part, that was borne out during our test runs.
When zooming in on tracked routes in our post-run analysis, the GTS 4's snake almost always roughly matched up to our Forerunner 955 Solar - a watch that also boasts dual-band GPS support.
However, we did notice that it had a very consistent tendency to slightly underreport distances. It's nothing major, but, if you're planning to run with this device over long distances, it's something to keep in mind.
As shown below, it works out to around a quarter-mile over a marathon distance.
Run 1: 00.1 miles under Garmin F955 Solar over 4 miles.
Run 2: 0.15 miles under Garmin F955 Solar over 11.2 miles.
Run 3: 0.05 miles under Garmin 955 Solar over 5.5 miles.
Run 4: 0.02 miles under Garmin 955 Solar over 3 miles.
Run 5: 0.04 miles under Garmin 955 Solar over 3.1 miles.
Considering the price, we think this is a superb performance. It's currently one of the cheaper wearables available with this more accurate dual-band GPS, and going roughly toe-to-toe with a premium Garmin model is very good going.
Heart rate monitor testing
Where the GPS accuracy of the GTS 4 impresses, our tests show that heart rate performance can be a little hit-and-miss.
Let's start with the bad. As shown in the interval session above, the Forerunner 955 Solar registers our maximum heart rate much higher than the Amazfit. Given these intervals required us to run at slightly above our goal race pace, there's simply no way that the 170bpm maximum on the Amazfit could be accurate - and Garmin's tracking performance shows this.
In the interest of confirming this, we also employed the Wahoo Tickr X chest strap on another intense run - this time with the pace steadily holding throughout.
Again, though, while the chest strap and the Garmin are within a couple of beats of each other, the GTS 4 is way off the mark. It's a real disappointment, and it does end up skewing a lot of other data within the Zepp app, too.
However, that's not to say it's completely unfit for purpose. During the steady, slow and very boring training run shown below - one in which we accidentally ended the tracking on the Amazfit GTS 4 around 8 miles in - the figures are much more comparable to the Forerunner 955 Solar.
It was a similar story during strength sessions. When the intensity is kept down - in the lowest three heart rate zones - there was no glaring disparity. The problems only begin at higher intensities, from our tests, and that includes both long bursts of intensity and short intervals.
With this in mind, the most crucial thing Amazfit has done in between generations is add support for external heart rate monitor pairing. That wasn't the case with the GTS 3, unfortunately, and we'd advise anybody performing more intense workouts to consider picking one up for use with the GTS 4.
Amazfit quotes eight days of battery life with the GTS 4, and, as with every smartwatch nowadays, what you actually get really depends on the features you're enabling and disabling.
In our last few weeks with the device, we've spent time with it with the always-on display on and off, and this, as you would expect, makes the biggest difference to how much you can expect to get.
With the display turned to always-on during our daytime schedule, alongside around 30-60 minutes of tracked GPS exercise, we would see a battery drain of around 20-25%.
Providing we were consistent, then, it would usually last 4-5 days.
It may be below Amazfit's estimate, but we actually think this is pretty good going for a tracker with a display this good and the additional power drain that dual-band GPS poses.
Of course, with the always-on display turned off, you can also stretch this out much further.
With the same kind of usage, tracking both sleep and exercise consistently, we estimate that the GTS 4 can manage around four weeks of battery life.
This is really solid, obviously, and there's even a battery-saving mode (that disables things like heart rate and sleep monitoring) for those who want to eke out even more.
Price and competition
For all its positives and negatives, the price of the Amazfit GTS 4 is one of its more curious factors. At least in terms of RRP, it's a chunk more expensive than we saw the GTS 3 offered at, and we're not entirely convinced the benefits are worth the extra outlay.
And if you look outside of Amazfit's own stable of watches, the surrounding competition is much stronger in 2022. The Samsung Galaxy Watch 4, particularly, is available through many retailers for the same price as the GTS 4's RRP, while you can pick up the Fitbit Versa 4 for a bit less.
Given that a watch like last year's Samsung flagship provides much more smartwatch functionality and integration with third-party apps, it's difficult to crown the GTS 4 as the top option under $200 / £200 / €200.
However, especially for those looking for more of a tracker than a phone companion, it's a viable option at this price. The value for money is still superb.
How we test