I bought mine about a year ago, and I think both the watch OS and many third party apps have improved dramatically since then. The third party apps I use regularly include Carrot Weather, Fantastical 2 (calendar), Bring (groceries), Due (reminders), Outliner Pro, Onenote, TickTick (tasks), Slack (communications). I also use the native timers, alarms, Siri, etc. I really like nightstand mode, and my wife appreciates it as well. After my initial alarm I will put the watch on so the snooze alarm is silent. I like the music controls and the ability to control our smart lights.
Every update has brought improvements, not just the big releases. Compared to one year ago my watch feels faster and more reliable. Hey Siri works much more consistently (problems are rare for me now). Not all third party apps are created equal, but the good ones open and refresh in two or three seconds for me, and I often get the info I need from complications. I'm looking forward to the improvements in Watch OS3, but I feel like we have already seen huge improvements in the last year. I don't know if I'd risk swimming with one, but many people do.
Sean