Apple now has a raft of different devices to pick between, after all, with the Series 9's most direct competition being the entry-level Apple Watch SE 2.
Refreshed just last year and featuring broadly the same watchOS 10 fitness tracking and everyday experience as what you'll find through the Series 9, the SE 2 is still a superb choice for most users.
With that said, there are also some serious differences between the Series 9 and SE 2 - and you'll need to know about them in order to pick up the right watch.
Below, we run through everything you need to know, including the distinctions between price, design, features, and more.
Starting at $219 / £219, the Apple Watch SE 2 is still comfortably the cheaper option of these two devices, despite the fact that the Series 9 begins at the same $399 / £399 tag as its predecessors.
As we'll explore below, there are also countless different case finishes, case sizes, cellular options, and band options to pick from, and these can all have a big impact on the price in your basket.
At the very least, you can expect to pay at least $150 / £150 more for the Series 9, so keep that in mind when digesting the differences below.
Case sizes and finishes
While the Apple Watch SE 2 features the same design profile we saw in the Apple Watch Series 4-6, the Series 9 continues the next progression of Apple's trademark square watch design.
The Series 9 offers no proper exterior design differences from what we got with the Series 7 and Series 8, meaning it's still only offered in 41mm and 45mm case sizes. The SE 2, meanwhile, is available in 40mm and 44mm.
As ever, you'll also have to decide whether you want the 'GPS' or 'GPS + Cellular' version of either of these devices, and it's also important to know there are price differences between these case sizes, too.
With the more premium Series 9, you'll also have the pick of more case finishes.
The SE 2 is only offered in aluminum cases, while those opting for the Series 9 have both aluminum and stainless steel exteriors to pick between. Naturally, there's a small weight difference to consider - around 10g for the stainless steel - alongside the price difference, but it's certainly a nice exclusive for the Series 9.
While it can be tricky to notice how these two watches differ when they're both turned off, seeing them with the display turned on is where you really begin to understand the rift.
Despite the Series 9 being only 1mm larger in both case sizes, the screen appears so much fuller and edge-to-edge.
Annoyingly, it's not actually clear just how much bigger it is than the SE 2's screen, with Apple keeping those details secret. However, we do know it's 20% more screen to play with - and a much more modern feel.
We've consistently touted this newer display style as one of the big reasons to upgrade, and that hasn't changed with what we've seen so far from the Series 9.
Always-on screen and brightness
With the Series 9 becoming the first Apple smartwatch (along with the Apple Watch Ultra 2) to offer a whopping 2,000 nits of brightness, this chasm in display quality has been widened even further.
By comparison, the maximum brightness of the SE 2 is 1,000 nits. It's not something we've been able to put to the test just yet, but we're keen to show a side-by-side of these maxed-out settings; we suspect it'll make a huge difference in direct sunlight.
Then there's the longstanding consideration of the always-on display, which has naturally been retained for the Series 9 but isn't available if you opt for the SE 2.
This isn't quite as big of a reason to upgrade, in our view, but it still takes a bit of the shine off the SE 2's daily experience.
Performance and watchOS
While we know that both of these devices can run the latest and greatest version of watchOS, it's also true that the Series 9 offers the more advanced S9 SiP chip.
Not only does this enable upgrades to the speed of Siri responses (with the voice assistant now able to handle some queries locally), but this should also deliver a noticeable bump in performance and the fluidity of animation in watch faces and menus.
However, since we can't run the two devices side-by-side just yet and really spot the differences in performance, it's difficult to grade just how big of an upgrade the S9 SiP provides over the SE 2's S8 architecture.
Stay tuned for more on this one.
Health tracking features
With no new additions to the Series 9 in the health tracking department, these two watches differ in the same way as we saw with the Series 8.
And despite this lack of new health insights, it's perhaps the area in which these devices differ the most when it comes to features.
There are serious health monitoring benefits to choosing the Series 9, with on-the-spot ECG readings, advanced insights into menstrual cycles via the temperature sensor, and blood oxygen saturation readings all offered.
Alone, we wouldn't necessarily say that these features represent a big reason to upgrade, which is why we still rate the SE 2 as a superb option for most users.
Still, when combined, they do begin to add up - and something like the temperature sensor could very easily become more functional over time and begin to provide further insights into Apple Watch sleep tracking, for example.
You'll still get a solid core of health metrics with the SE 2, however. Features like Fall Detection, Crash Detection, irregular heart rhythm notifications, high/low heart rate notifications, and Emergency SOS are all available on the watch, while Apple Health will be brimming with even more insights.
Battery life and charging
With Apple continuing to solemnly stick to the promise of an 18-hour battery life for the Series 9, this is one of the few areas that can be matched by the SE 2.
And given that you're likely to be charging your watch every day or two, this is where charging times can actually make a big difference.
We're yet to get our hands on the Series 9 and really compare this side-by-side with the SE 2, but our experience with the fast charging support of the Series 8 (and older) devices showed us that the latter's lack of it does hold it back.
The Series 9 is still only likely to be 15-20 minutes quicker at going from a flat battery to 80%, but, as we've alluded to throughout, each key area of the watch experience offers this kind of marginal gain.
And, of course, if you do want noticeably better battery life, the Apple Watch Ultra (or Ultra 2) is still the one you should consider.
Ultra Wideband and gesture control
While it may seem minor on paper, the SE 2 also misses out on Apple's second-gen Ultra Wideband chip that's present in the Series 9.
So, what does this actually mean? Well, not only does the UWB chip help out with the Find My app, but it can now also provide detailed directional on-watch instructions to help relocate your iPhone (as long as you have one of the iPhone 15 models).
This isn't the only feature enabled by the Series 9's improved internals, with the latest device's Neural Engine enabling the new 'double tap' gesture.
This essentially unlocks one-handed control of the watch, with a quick double tap of the index finger and thumb controlling the primary button on the watch face.
This can be used to answer calls, scroll through menus, remotely control the iPhone's camera, and much more we're yet to fully test out, we're sure.
We're still waiting to see just how much these two new features help out in the everyday use of the Series 9 - particularly double tap - but they do have the potential to widen the margins considerably between it and the SE 2.
Initial verdict: Which is best?
With the Series 9 offering an upgrade in almost every area, there's no real debate about which of these two smartwatches is better.
Like with the Series 8 before it, choosing between the Series 9 and SE 2 is instead all about how much you believe the upgrades are worth the extra price.
We'll be able to add more detail to help answer this once we've tested out all-new features like the Series 9's screen brightness and gesture control, but the biggest upgrades are ones carried over from older generations.
And while we do believe the SE 2 is certainly good enough for most users, we also think the more premium design and advanced features are reason enough to spend the money and upgrade.
For those who just want a basic Apple Watch to encourage a more active lifestyle, however, or those who don't believe they'll appreciate the added benefits, the SE 2 is likely the best pick.
How we test