I've spent my first full day wearing my 38mm Apple Watch Sport. Coming from a Pebble, I'm very pleased how well the watch integrates with the functions of the iPhone and addresses some of my issues with the Pebble (which I still loved). First surprise, Apple sold themselves short on the battery life. Over 13 hours today I have checked and replied to notifications, used the watch for 2 hours of navigation, had a 15 minute conversation, used the MLB at Bat app to follow the Yankees game a few times, messed around with my watch face, and checked a few things periodically like the weather. I also have prominent haptics enabled and 2/3 brightness. I'm currently at 72% battery remaining. Very impressed and surprised. The taptic engine is EXTREMELY subtle. I enabled prominent haptics and this helped tremendously. It vibrates more heavily (though still silently) before important notifications like text messages but not before every notification. After a day, however, I'm getting used to the taptic engine and noticing it much more regularly. The watch faces are all great, though I wish more of the digital faces allowed for complications. The force touch feature is very cool, as well as the crown, and the UI does not take much time to get used to. Phone conversations work well, though I would certainly use my iPhone in public or with a longer conversation. It was convenient for walking around while doing other things. I could hear the other person well and they had no idea I wasn't using my iPhone. A couple negatives. The screen turns off sometimes when I don't want it to. Minor annoyance but I'd like to be able to adjust the length of time it stays open. As others have said, third party apps are also fairly slow. I hope everyone else is enjoying their watches too!