The Apple Watch 10 is a solid replacement for the Apple Watch Ultra (and it's currently on sale)

ZDNET's key takeaways

• I tested the 46mm Apple Watch Series 10 model, priced at $529.
• The new watch body is charmingly thin, the larger display is lovely, fast charging is greatly appreciated
• Battery life remains rated for 18 hours, and the watch is still missing some software features found on the Watch Ultra 2

What's the sale, and will it expire?

Several online retailers have reduced the price of the Apple Watch Series 10. Amazon is currently selling the 46mm model with the aluminum case for $410. On Best Buy's website, you can purchase the smaller 42mm wearable for $400. It's unknown when the deal will expire, although we suspect these price drops will only be around for a limited time.

There are many great smartwatches on sale for October Prime Day. Sometimes, you can get up to $100 off a wearable. To find them, be sure to check out ZDNET's roundup of the 23 best smartwatch and fitness tracker deals for October Prime Day.

With my larger wrists and preference for rugged watches designed for outdoor activities, the Apple Watch Ultra 2 has been my go-to wearable over the past year. On the other hand, the more mainstream Apple Watch Series models always felt too small and limited to meet my needs. That's why I was delighted when the new Series 10 was announced last month, with larger displays and thinner designs than ever before.

Also: The best Apple Watches we've tested (and where the Series 10 stands)

After trying the new Jet Black 46mm Apple Watch Series 10, I wouldn't go as far as to say it beats the Watch Ultra 2, but the newer model certainly offers compelling features that will likely appeal to most users. Here's what I liked about the latest Apple Watch and what could be done better going into next year.

After unboxing, pairing, and strapping the Apple Watch Series 10, the first thing that stood out to me was its incredibly slim profile. At just 9.7mm thick -- compared to the 14.4mm thickness of the Watch Ultra 2 -- how Apple managed to fit all the necessary sensors, electronics, batteries, and antennas into such a compact design is quite the engineering marvel. 

The thin and lightweight build not only feels great on the wrist, but it also makes sleep tracking far more comfortable than with the Watch Ultra 2 (and any other bulky wearable), which protrudes an extra 4.7 mm and can feel a bit bulky overnight.  

Also: I was on the fence with the Apple Watch 10, but these 3 features changed my mind

One of the standout features, especially for sleep-tracking enthusiasts, is the Apple Watch's new ability to monitor sleep disturbances more precisely. The Series 10 uses the accelerometer to estimate interruptions in your breathing, aiming to detect potential signs of sleep apnea. 

While there isn't a dedicated sleep apnea app, Apple Health on the iPhone now displays any breathing disturbances in the respiratory section. An algorithm analyzes these patterns and alerts you if it detects possible sleep apnea, which you can then discuss with a healthcare provider. (Remember, all of this pre-visit information is not professional medical advice.) Fortunately for me, I sleep like a hibernating bear and haven't had any issues with my sleep quality.

Matthew Miller/ZDNET

One of the standout features of the 46mm Series 10 is the larger display. While it only offers 3% more screen area than the Watch Ultra 2, the reduced bezel around the display makes it feel significantly larger. The Series 10 also features a wide-angle OLED, which makes it easy to read the screen even when viewed from an angle -- perfect for quick glances throughout the day.

However, I've been a bit spoiled by the impressive battery life of the Watch Ultra 2, which easily lasts two full nights and two full days on a single charge. In contrast, the Series 10 requires daily charging, but Apple has thankfully integrated faster charging technology. You can now reach up to 80% battery in just 30 minutes or get around eight hours of use from a quick 15-minute charge. 

Personally, I've made it part of my routine to take the watch off in the morning and charge it while getting ready for the day, which gives me more than enough battery to last until the next morning. That's to say. for most people, the Series 10's thinner and lighter design is well worth the trade-off in battery life.

Also: Your Apple Watch is getting an upgrade - here are the best features in WatchOS 11

As impressive as the Apple Watch Series 10 is -- and I expect it will appeal to most people looking for the best Apple Watch -- there are still three key reasons why I won't be switching away from my Watch Ultra 2.

Rugged Design: I regularly bump my watch while running, hiking, mountain biking, and fly fishing, so I need a device that can take a beating. The Watch Ultra 2's titanium body provides solid protection for the sapphire glass display while also safeguarding the right-side button and digital crown. I also regularly use the Action button to quickly launch the flashlight -- a feature I've come to rely on.

Siren: Now in my mid-50s, I often enjoy outdoor activities on my own, so having a reliable safety feature like the Ultra 2's siren gives me peace of mind. I've taken a few spills while trail running and biking, so knowing I have an easy way to signal for help when something like that happens again is a significant plus.

Precision Start & Night Mode watch face: One of my biggest pet peeves with fitness watches is the mandatory countdown before starting an activity. I was disappointed to experience this with the Apple Watch Series 10 on my first run. The Watch Ultra 2, however, offers a precision start GPS option, allowing me to lock in a GPS signal and finish any last-minute prep before starting the activity -- no frustrating countdown. 

Also: I changed these 8 Apple Watch settings to significantly improve battery life

I hope this feature gets rolled out to all Apple Watch models in a future software update. Another feature I love is the Ultra 2's night mode watch face, which turns everything red at night to preserve night vision. Other watches, like the Garmin OLED and Amazfit T-Rex 3, also offer red or green text for better visibility in the dark. Again, this seems like a feature that could easily be provided with a software update for all Apple Watches.

Matthew Miller/ZDNET

I want to make it clear that while the Watch Ultra 2 packs several advanced features, Apple's software is so intuitive that many of these extras might not make a huge difference to the regular consumer. I realize that I'm part of a niche group of watch users who value aspects like durability and safety features above all else. You may not have the same qualms with the Apple Watch Series 10 as me.

Also: 6 compelling reasons to buy an Apple Watch, according to a wearables expert

The Apple Watch Series 10 launches with WatchOS 11, which introduces the Vitals app, Training Load, Smart Stack with gesture support, U.S. national park maps, and much more. The gestures on the Series 10 work flawlessly, and in my experience, they're much more reliable compared to the swipe and finger-tapping inputs of other wearables, including the Samsung Galaxy Watch Ultra.

ZDNET's buying advice

Apple has made some solid improvements with the Watch Series 10, which remains the best smartwatch on the market today. The Jet Black finish is particularly stunning if you prefer that classic, glossy iPhone 7 aesthetic, and it pairs nicely with a wide variety of watch bands.  

The Watch Series 10 retains the signature squircle design we first saw a decade ago, but with its sleek 9.7 mm thickness, it practically disappears on your wrist while still packing in cutting-edge technology. Fast charging is a welcome addition, and WatchOS 11 truly elevates health and wellness tracking to the next level.