Since most of the tone seems to be "meh" or outright dislike I thought I would chime in with a different view. Like Billy Bats, I wasn't planning on buying one but did want one. As it happened, I did win the Sport edition (aluminum) in a sales contest at work. I had a Pebble previously and gave up on it after about 3 weeks. I joked that the Pebble basically was a reminder to pull my phone out. I find the Apple Watch to be much different and much better.
First, they absolutely nailed the way it interacts with you. I keep the ringer off on my phone and on the watch and the gentle shaking when I get an email, text, or call is just right. It even works great for my morning alarm (more on that in a bit).
Second, I think the notifications are great. Unlike the pebble, this actually helps me keep my phone IN my pocket more. I have five active email addresses between work, personal, and side projects. My wife's first/default nag with me when we are in a disagreement is that I spend too much time on my phone. And she's right; I pull my phone out way too much, especially when I'm with my family. So many messages--most of them, probably-- don't really require immediate attention. Some require no attention at all. Seeing the message and archiving it takes less than a second and gives us each what we want: I spend less time on my phone but I don't feel disconnected from my work and businesses.
I do use it to tell time as well. The faces may be seen as "fun" but they have a real utility to them. If people crow about Android being customizable and how awesome that is then Apple Watch owners can do the same about the watch faces. Most of the time I use a custom face that shows me my alarm, battery life, outside temperature, and when my next calendar appointment is. My kids are amused by the Mickey Mouse watch face as well, a level of entertainment to my small children no different than games and stuff on a regular phone.
The activity app is a nice-to-have, mostly because I did nothing with FitBit or activity tracking prior. I don't get enough exercise and I know it. At least with this simple activity tracker I can be informed of how lazy I am and actually try. If it gets later in the afternoon and I'm way behind on calories/steps I'll take a walk around downtown for 20 minutes. Depending on your perspective that may or may not be a lifechanging feature; I'm sure my heart appreciates that I'm actually trying though.
The watch is well weighed and well built. I actually cut the lawn (Texas weather ya'll) the other day and forgot it was on my wrist. Even with me sweating like crazy it remained comfortable whereas my other (Dress) watches would of course have no business on my wrist while working in the yard.
Perhaps my favorite feature is the alarm. I use the Watch to wake up in the morning at 5:15 with a light buzz of my wrist. If you ignore it long enough a small chime comes in, escalating in frequency until you finally wake up. This is a great alternative to a shrill alarm clock that wakes up me, my wife, and the aforementioned two small children. The Watch helps all of us wake up and sleep better.
Finally, I travel often for work and the Passbook integration (Boarding passes, hotel room keys) and Uber app (best app bar none. press the button, car arrives) are quite useful. They solve first-world quasi-problems but what's wrong with using technology for added convenience?
I have apps like HipChat and Slack (work) and sports stuff that I pretty much never check ever. Also don't use Siri or voice commands. I realize most of what's above seems inconsequential. They are incremental changes to my day and I admit that most of them aren't earthshattering. But not pulling my phone out so often, actually getting a little exercise, and waking up less chaotically make me glad to have the watch.