For me there are a few things i like and I dont like.
The Good
1) The connectivity is magical. We have all used bluetooth and wifi devices before, paring is a pain, they drop out for no reason, if you go out of ranges and you are screwed for a reconnection etc. Not the apple watch, its wireless connectivity how it should be.
2) The interface, despite what people say its not that hard. Everything is considered and there are plenty of shortcuts. Force touch is so simple why have people not thought of it before.
3) Battery is great, not nearly bad as I was expecting. Your phone WILL be the first to die.
The Bad
1) Siri is still god awful. But even worse on the watch because you CANT FIX HER! Sure you can delete the entire message and start again, if it hasn't already auto sent your embarrassing sirifail first. People who say how amazing she is on the watch please hook me up with your drug dealer! Seriously, Siri is WORSE on the watch, as she she has all the problems from the phone version, but now with even more connectivity problems, no way to fix her mishearing, and a lucky dip of functions that are supported on the watch or not. Seriously this is a bad issue.
2) Not apples fault but god there needs to be a Facebook app already. Its killing me.
3) Glances need to load in the background NOT when you have selected them. The watch needs to be smart enough to go "Oh shit, he has swiped up glances, maybe I should load maps and other glances information, while he is checking his heart rate". Because as it stands right now is swipe and wait, which kind of defeats the purpose of the glances.