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

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I still use my Watch 3 with Samsung Health actually! Thankfully I haven't had any glaring issues, maybe just the GPS route tracking but I've never really used that feature to begin with. I mainly use it for running.
Most Galaxy watches need to be charged daily and the sleep monitoring system is annoying. The health app needs to stay opened to monitor sleeping patterns for the night. On the plus side, the watch now does blood pressure (and it's approved by the FDA). Fitbit was great until they started the monthly fees for their ecosystem. I really wasn't upset when I lost mine doing yardwork and I replaced it with a Galaxy 6. I am 71 and I love mine. I wasn't thrilled about the need to change it so often tho. It's over 2 years old, and now, sadly, it doesn't last a minute over 24 hours. I get alarmed when it turns itself off (and I'm just relieved when I can turn it back on after half an hour on the charger). I recently started keeping an extra charger in my car just in case. Yesterday, I found a place that will replace my battery. It seems like a lot of money, nearly half the original cost, but buying the 8 would cost a lot more now. I don't think that the slight improvement between the 6 and 8 technology is worth the upgrade yet. I plan to wait until they have batteries that last longer than a day. (I still have my ancient Galaxy 3 because I love the rotating bezel).
In the same boat here. Exact same switch and exact same sentiment.
Got an S50 coming from a Galaxy watch 3. Will never go back. It's lighter, battery is 10 days compared to 1, and does everything I actually used the Galaxy for except make/receive calls and honestly that was more a novelty than a useful feature.
I'm still on the 3, and it still does everything I want. Thinking about upgrading but only because I want my MIL to have something with fall detection and I would give her my 3 for that, otherwise, its good
I love the look of my stainless Samsung Galaxy watch 3, but newer versions are not IOS compatible. I was looking at the Huawei GT 6 as a replacement but they aren’t available for purchase in the US any more. The Garmin Venu checks all the boxes for me but the price is more than I want to spend.
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

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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