Garmin
Forerunner 255 Series
Long battery; but wrist HR tracking is inconsistent.

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The Galaxy Watch Ultra would be the best choice. Next would be Galaxy 5 Pro. Although my Pixel Watch 4 gets longer battery life than my Ultra does.
Bro, why did you upgrade from 7? I have the Watch 5 Pro, and I don't think I need an upgrade. You said that there are small changes; I think those don't matter too much.
Yes! I had the Galaxy 5pro for 2 years and was training for a half and was looking for a better fitness watch. I did switch to Garmin 4runner, which was awesome for that purpose but hated it as a smartwatch. When the Ultra came out I sold the Garmin and upgraded to that hoping it would be better. It really was more the same for fitness as the pro, but heavier and chunkier on my wrist and I think sleep was even worse somehow. Finally I sold the Ultra and moved to the pixel 3, been with it for 3 months now about and love it. Not as good as the Garmin with all the stats and metrics they throw at you but tracking has been great and I really like Fitbit way more then Samsung Health. My big issues with Samsung Health is what ever algorithms and their new AI they are using is off like almost on everything but I really noticed it on sleep but it's everywhere. I don't know if it's because of the watch sensors or with it or anything to do with it but man most the time its funky. Also, I know this is subjective, the UI on the pixels is way better, I feel like oneUI is dated and needs an update. I left before the last update so not sure if it got better though but going to pixel watch I think it's better looking. Again subjective. The pixel has been great so far not sure I will upgrade to the 4 until reviews come in as it doesn't seem the 3-4 will be a major upgrade yet but if your going to switch I would wait for the 4 to get the latest. unless price is a factor might score a deal on a 3.
Well, like the 5 Pro, the Ultra has a bigger battery and will last you up to \~3 days, whereas the 8 Classic has a smaller battery, which will probably last you \~1,5 - 2 days. Also, the 8 Classic has a significantly smaller screen than the Ultra, and even its biggest version (44mm) is 1mm smaller than the 5 Pro, which is 45mm. Two days ago, I was in the same situation you are right now. I absolutely loved my 5 Pro and wanted something similar in terms of (battery) performance and I wanted something that felt as robust as the 5 Pro, and after careful consideration I could only go for the Galaxy Watch Ultra. I've been very happy with it - it looks absolutely stunning.
I'm new to PW and I have a 3 and I haven't had any issues except for changing notification sounds and accessing photos on my PW3. I have a Samsung watch5 Pro which I can do all those little features. I'm still on the fence with the PW3
galaxy watch 5 pro best for battery and fitness balance
Garmin
Forerunner 255 Series
Long battery; but wrist HR tracking is inconsistent.

Garmin
Forerunner 955 Series
Best value, clear MIP screen; limited smartwatch features.

Garmin
Fenix 7 Series
Durable, multi-week battery, flashlight; high price, buggy software.
Garmin
Instinct 2 Series
Rugged, solar multi-week battery; bulky, small screen readability issues.

Garmin
Enduro 3
Multi-week solar battery, lightweight; but bulky form factor.

Ranked #1
Oura - Oura Ring Series

Ranked #1
Apple - Ultra Series

Ranked #1
Garmin - Enduro 3

Ranked #1
Garmin - Fenix 7 Series

Ranked #1
Garmin - Forerunner 255 Series

Ranked #1
Oura - Oura Ring Series