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

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Pixel watch 4 is the first Pixel watch where I havn't had to ever worry about battery life, few minutes charge during a shower and it's good to go. This has also resulted in me wearing it pretty much everyday, all day. Previous Pixel watches I would often set down the charge and then forget to put back on. I would 100% upgrade from 2 to 4, even 3 to 4 is a significant enough improvement for me. I traded in my 1 when I got the 4 (still have the 2 and 3 that I hand down to family) and it was actually laughable to handle it again, it's tiny for a start with an even tinier screen due to huge bezel, I also remember the battery life was terrible. We have come a long way and I'm excited for the 5!
Currently using Samsung Galaxy Ultra, Moto Fit, and Google Pixel Watch 4. Ive used the Samsung the longest and is favored. Pixel is giving it a run for its money though. They both have cellular plans and both work well. The Moto is great at battery, used it a week without putting it on the charger. The other three I am putting on the charger every other day usually. If it wasn't for the domed glass of the Pixel, it would be favored. Knock on wood, it lasts for two years. I do have them tied to their respective company phones too. Workouts are similar however im still testing them out. Out of these three, I would suggest the Samsung. However if you don't have a Samsung, the Pixel.
I charge my Pixel Watch 4 about once a week. My Samsung Galaxy Ultra is every other day. Garmin may be what you're looking for though
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.
I got 24hrs+ on pw1 with this on. Now on PW4 and 50% down after 20 hrs
I'm impressed too. Coming from PW2. Currently I'm on the 25th hour with a 70 minute tracking workout(10 min treadmill, 60 strength training ) and it's on 56 %.
PW4 ? I have touch to wake, rise to talk turned and always on screen turned off. I'm just not s big fan of those three.
It just dawned on me that 30-40 hour real-world battery life means you are effectively charging your watch daily - so how does it monitor sleep patterns (meaning, it can't) since charging while asleep would seem to be usual, as opposed to when you're up and running around.
I was at a real live Google Store and asked about swapping out the band (I don't like the Fitbit style tuck-tail design.) Interesting enough the Google Store watch "expert" took 15 minutes to demonstrate exchanging the band on the PW4. Yikes! If she couldn't, what chance do I have? I don't expect Google to keep the store in business for a year, much less to be around when I need to replace the strap.
I am "this close" to pre-ordering the PW4. I called Google and asked about LTE in Europe & Asia, and what functions are lost if LTE is turned off (and will the LTE watch Bluetooth connect to an Android phone without functionality loss). The Google specialist will get back to me on this - but maybe there is an answer to be had here? I am confused about LTE not being able to connect to 5G towers but works with WiFi. Maybe I'm having a vernacular problem. Can somebody explain what's going on? I thought 5G (5gh bandwidth) was wifi in a faster flowing pipe? TIA
Pixel watch 3 or 4. Both will last you comfortably more than 24h, especially the 4. Some of the best sensors and sleep tracking there is. A step down on health tracking but by no means bad is the oneplus watch 3. Much better battery life and tougher build.
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.

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Oura - Oura Ring Series

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Apple - Ultra Series

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Garmin - Enduro 3

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Garmin - Fenix 7 Series

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Garmin - Forerunner 255 Series

Ranked #1
Oura - Oura Ring Series