This head-to-head doesn't represent the typical choice between a new-gen and old-gen model, in which the latest model often represents the best experience for most people.
Google and Fitbit have changed the make-up of this smartwatch line relatively drastically between generations, and that means there are very distinct pros and cons to each model.
Luckily for those hunting down the key differences, we've tested both thoroughly over the last couple of months, and are able to deliver our hands-on experience of everything that's changed - as well as a few things that have remained the same.
Quick verdict: Fitbit Versa 4 vs. Versa 3
The Versa 4 and Versa 3 are both incredibly similar and different - and which is the better pick for you really depends on what kind of user you are.
If you already know you're looking for a watch with the likes of Google Assistant, third-party apps and watch faces, you have no real option but to plump for the Versa 3. Or, alternatively, the Google Pixel Watch, if you don't mind putting up with much weaker battery life.
Unless these services and features mean something to you, though, or you want to avoid paying the loftier asking price, the Versa 4 is the slightly better smartwatch thanks to design tweaks, tracking upgrades and the presence of Google Maps and Wallet.
Should you upgrade from Versa 3 to Versa 4?
If you already have the Fitbit Versa 3, we would not recommend upgrading to the Versa 4.
The lack of third-party support and the fact there are no meaningful improvements elsewhere make it a difficult device to recommend to existing Fitbit smartwatch owners.
1. Apps and smart features
This is the biggest point of comparison between the Versa 4 and Versa 3, and, as we've highlighted above, will likely sway which is the better fit for your needs.
While the third-party app and watch face support on Versa 3 was limited, it was at least present, giving you access to the likes of Strava, Fitbit and more. The Versa 4, however, gives you nothing of the sort.
Aside from integration with Google Maps and Google Wallet (but not Google Assistant, strangely, which has been dropped), you're not getting apps or even third-party watch faces on the smartwatch, as the smartwatch doesn't have Wi-Fi support.
At least at the time of writing, this support is still present for the Versa 3, though it doesn't feature the same integration with Google Maps and Wallet.
The Versa 3 is now over two years old, launching in 2020, whereas the Versa 4 was only released in September. That means there's a natural price disparity between the pair.
For the newer Versa 4, you're looking at paying $229.95 / £199.99 / €229.95. This is the same price the Versa 3 initially launched at, though this is now available for around $159 / £169 / €199.
We would also note that both are frequently heavily discounted, so finding them cheaper than the above rate isn't too difficult.
At the RRP, the Versa 3 offers undoubtedly better value, but neither sits in what we would describe as anything more than decent value for money, particularly with the Fitbit Premium subscription required to get the most out of the experience.
Though the app situation is certainly a reason to avoid the Versa 4, the minimal design changes Fitbit and Google have made are most welcome.
Though this pair looks very similar at first glance, the newer model has had the side button reintroduced, making navigation around the device much simpler.
It's a much nicer experience than what's offered in the Versa 3, which instead has a capacitive groove, and is located a little bit further down the side of the case.
Aside from this, and the fact the Versa 4 is slightly thinner, there's not really much to speak of. And that's no bad thing - we think the look of the Versa is strong. With the band mechanism still the same, too, it makes it easy for those willing to upgrade.
4. Fitness tracking
Not much has changed on the tracking front, with the same array of sensors and tracked metrics being registered from both devices.
The real improvement the Versa 4 offers is the 20 new exercise modes, allowing users to track the likes of HIIT, dancing and CrossFit workouts. This doubles the number of exercise profiles you'll receive on the Versa 3, which is limited to 20.
5. Battery life
The battery life isn't different between these models, but that's not something to be concerned about.
Whichever you choose, you're getting a device that can last around a week in full use - and that's much more than many other, more expensive smartwatches out there.
During testing for both, we found the daily drop-off to be around 10-15%. If you include tracked GPS exercise for about an hour, this alone will also shave off around 10%.
The charging situation is also positive, and you can get over a day of use from just 15 minutes on the cradle.