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

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Ha, just got T-Rex Pro. I kinda like it!
My voice note “jeebus I took a left when I shoulda gone right.”
I got the Amazfit T-Rex Pro for way cheaper than Coros or Garmin and I love it -it has everything I need (the most important I wanted was map/gpx navigation.) it has great battery life.
I upgraded from Epix 2 to T Rex Pro. Amazfit lacks a few things (for example, the running data panels are not very customizable), but overall I'm very happy with it. I tried running with both watches on my wrists, and the data was slightly more accurate on the T Rex. Very good and valid data (Amazfit had a strap, and Garmin had its own triathlon heart rate monitor). The Amazfit app is a little less complete, but each update improves it significantly.
I’m on the fence about getting another Amazfit and am considering the new Active 3. I bought a T-Rex Pro in late 2023 for $100 on sale, and the battery died about 2½ years later. Great watch for my use, but now it is 3xs the price. Before that, another Amazfit that only lasted 14 months. I preferred using an alternative app which is more accurate over Zepp, which still feels stagnant and gimmicky. I don't need a smart watch app to help me get my Chakras in order. The best-built and best-looking watch I’ve owned was a Huawei GT, solid, premium, and long-lasting, but software restrictions in the U.S. make it a hassle to use. My Garmin Fenix (bought on sale for $450) lasted five years and had far better software, especially with the online mapping and activity management. I’ve also looked at the Kospet Tank M4, but it’s huge and looks like a brick and a toy on most wrists. Amazfit prices seem to have doubled, and newer models look more sealed and harder to repair. I’m going to try replacing the battery in my T-Rex Pro, which I loved, but at roughly $50 -$100+ per year of lifespan, these watches are built with planned obsolescence in mind. If Amazfit prices keep climbing and they keep pushing gimmicky subscriptions, I’ll probably just go back to Garmin.
Amazfit trex. I have the trex pro, but the newer 3 and ultra are pretty cool. I think they are all less than 300
If you don't have Garmin money, or just don't want to spend that much, Amazfit has some decent watches at a reasonable price. I've been using the trex pro for 3 or 4 years, and it's been great.
I have in the past but now I use a dedicated bike computer. There are some well within your budget that have maps and would be way better than trying to navigate using a small watch screen. There are a couple of Magene computers you can get on AliExpress that are highly rated for the $$. If you are really committed to having a watch, there are a lot of Garmin competitors that would work. I'm thinking Amazfit Trex (or one of the many other watches in the range), Huawei GT etc. off the top of my head.
Best device for hr measurement is a chest strap. Polar h10 is better than any watch out there and costs pennies and you can pair it with your mobile. Watch is still a good thing to have. Garmins are top notch (I have one myself), but a friend of mine bought an amazfit and I have to admit that it's close while costs 50% of the garmin price. Apple is more of a phone. Good for streaming the music etc, but it's not the best sportwatch out there.
I use fenix 8 solar, previously had fenix 6 pro and fenix 5 before that. My wife has venue 3. All are excellent. I use HR strap for when I care about HR. Fenix 8 has probably the best sensor from all the farmins, but still a 50$ strap is more accurate. I have no experience with forerunner series. Heard some good stuff, but I dont know what models are better than the others. I would really look at the amazfit rather than an entry level garmin now. $500 amazfit trex is very close to my $1000 fenix.
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

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Oura - Oura Ring Series