I like my Fossil Q Explorist well enough. I have the Gen 3 which doesn't have the heart rate monitor or GPS, but on the whole it's a good watch. If you want a smart watch that can do all the smart stuff and last a couple days, I'd look elsewhere. Fossil watches don't have the best battery life. The Gen 4 says like 2 days on standby a day with usage. I get about 6-8 hours tops actually using the watch (looking at notifications quickly and swiping them away, looking at the time, changing songs on my phone), and the charge time is like 3 hours. They suggest it can do sleep tracking, but I've never tested it because I need to charge it every night.

If you don't mind having a watch that is mostly for doing watch things, and then charging it every night - Fossil is nice. But I would look elsewhere if you want a smart watch for daily use doing "smart" things.