Absolutely. My phone can be in the other room, or in my pocket, and I can see all my notifications on my wrist, when sometimes I wouldn't see a text/call for a long time because I usually always keep my phone on silent because the dings and vibrations are too annoying. The "tap" from the watch is nice and hasn't annoyed me once. Siri is very responsive, and I can quickly reply to a text message on the go without ever touching my phone.
I find myself encouraged the fill the activity rings, and like getting progress updates throughout the day. When my watch taps me to stand up after I've been sitting for too long, I do just that when normally I wouldn't have. These are little things, but the watch isn't meant to take over and be a do-all must-have gadget in your life.
A lot of people are expecting it to do things that Apple didn't account for it to do for a reason, and like anything, of course, there are always improvements to be made, but that's technology. I'm not the kind of person who needs the newest things (I've had my iPhone 5 for over 2 years and haven't gotten a replacement yet, and I'm perfectly happy with it), but I love wearing a watch, and you won't find yourself constantly on your watch, surfing the web, because you can't, but that's the beauty of it. It's an added convenience, and while I would normally spend in the 200-300 range for a nice watch, this seemed perfectly reasonable.
The people who are complaining that it doesn't do everything perfectly, or doesn't do enough yet, or 3rd party apps are horrible are expecting too much out of it, too soon. Just enjoy the simplicity of what it can do and you will be extremely glad you bought it