I've had mine since October of last year. I'll say this first: I probably don't take full advantage of my watch's features, but I still love it; I feel lost when I forget to put it on, and have, on the few occasions that has happened, turned around and gone back for it.
I use it mostly for:
-Smartlock device for my phone
-Music controls (google play music)
-Telling time (I rarely change the watch face. If I do, it's usually between a classic chronograph style, and a star trek theme)
-Putting my phone in do not disturb mode
-Setting timers at work
-Replying to texts while driving (via voice response) <--- do this very rarely as 1. it's still distracting and 2. it doesn't always work well
-Finding my phone in the house when I forget where I left it (happens at least once ever couple of days)
-Quick glance of notifications to see if I need to respond ASAP or can wait until I actually have spare time.
As far as the longevity of it, it's still getting current updates, and already has speaker support that other watches that came out around the same time do not. It doesn't really do any biometrics (heart rate, etc) like others do, and the step count seems iffy at best like most others.
All that being said, it was the cheapest available android wear watch when I got it (and might still be?) at $149. I've been very happy with it, and still get a lot of compliments on it. I'd buy it again, but I'd also check to see if a new gen is coming out soon.