If you order a Garmin look at the extended warrantee (If you order one via Amazon they will sell you an extended warrantee, I am sure that others will too). My vívoactive® HR lasted one year and one week before it died.
As for GPS accuracy, they will be accurate to within yards, the question is how much time do they sleep between fixes (in attempt to save battery).
If I was to order another Garmin (depending on the Apple watch 3, in about a month) I would order a higher end one with a sapphire lens, as the plastic one scratches up fairly easily.
I am going to look at the Apple watch 3 (they have an option one the Apple watch 2 for ones with sapphire face) and then see what Gamin has at the time. I very much like the idea of the Apple watch, but not that it needs to be charged every night. The Garmin has a good life on it. Fitbit is interesting, but they don't have a waterproof one with a screen and built in GPS.