I have been an Amazfit user for several years and I finally decided to switch to Apple Watch after watching many reviews and videos, maybe a week of use is not enough but I can now make a verdict:

My negative thoughts:
I miss the autonomy of Amazfit watches, the Apple Watch 9 barely lasts two days with regular use, my old GTS 4 lasted the entire week.
Using the Apple Watch for the first time I found the worst surprise that I had not seen in the reviews, the auto-brightness cannot be turned off and in a dark room you can barely read the screen, I will have to deal with that.
My positive thoughts:
Everything else, I loved the app on the iPhone, I loved the watch faces, I loved the integration with the Nike Run App and Strava, I loved how all the sensors work on this watch, better than on Amazfit, I loved the brightness peak of the screen in daylight, and I loved the number of apps compatible with Apple Watch, many more apps than Amazfit.
If it weren't for the battery and the auto brightness I would give it 5 stars

Many people say that if you are a series 6,7,8 user, the jump to series 9 is worthless, not a big difference.
But I can say that if is your first time with apple watch, you must try series 9, ultra if you want to spend a pair of extra hundreds.

overall good, but it is not as good as I thought, the software configurations are a little confusing on the watch

Love the Apple Watch series 9, and up grade from series 4. You can personalize face with 24 pictures when you raise your wrist. I love looking at all the different pictures of my family throughout the work day. I got the bigger screen size 45 mm size, I do have a small wrist but the 45 mm size still look great (not to big). Easy to use seri to add apts, set alarms, track fitness and health ect.

I have (male) small wrists to got the 41mm version. Fit's well, and is easier to get on/off the a prior Fitbit. There's so much tailor-ability (faces and allowed "complications") that it's initially overwhelming. Figuring out what you need/want and which face/faces allow these becomes a challenge. Adjustments can mostly be done on an iPhone (can't really use an iPad or Mac OSx computer for this). Battery lasts about 36-hours before needing recharging. Suggest having one of the "complications" (displays on the periphery) be the battery level. In short, you'll need some time to fit the display to your needs (via an iPhone). Otherwise, comfortable, reasonably light and non-intrusive. Just be prepared to recharge every day or 1-1/2 days with the included charger. Takes about 45 mins. to go from 20% to nearly full charge. Maybe less.

After I got my first iPhone in October, my Fitbit app barely worked. Took forever to refresh and I couldn't even see weather or sleep.

Apple Watch is amazing. It's beautiful. It lasts thru a night of sleep and a run per day. Charges fast. I can make calls and messages from my wrist and place emergency calls. I'm never without my phone so I don't need cellular, it functions via Bluetooth. I can control what's playing from my wrist, see stocks, check email if needed, track mood, and I set up my watch face for ultimate self help using the "I Am" affirmations app. Also, heart rate to remember I'm alive, bear app which is notes with voice dictation (works great), voice note and mindfulness (which has mindful modules but also log your mood/state with detailed emotion options). It's really great. The watch just WORKS. Makes Fitbit look like a hunk of garbage. I feel safer too since watch has fall detection (I'm a runner), tracks location on find my phone for my parents, has photos (I can view up to 500 so I keep an SOS mental health folder of images and snippet that calm me down), maps (really important for walking without phone out). The alarm is great, best of all it syncs perfectly with my phone so if I have maps on my phone on silent I still get a buzz before directions so I can mute instructions but not have to look down at phone wondering when my next turn is. Has reminders app, audible, cycle tracking. The Apple health app is a league above anything I've ever seen.

The exercise app gives a huge amount of data for running (cadence, heart rate, elevation gain and loss, pace) and you can use other apps while during a workout ie check messages or place call during a long run.

It has great sleep data and is much more accurate than Fitbit who tries to make you pay for same data. Fitbit even erased the community function while Apple fitness allows you to see others workout and compete.

Love!!