Guess i must have made a mistake then - my AW device was at best 10-12hours.
No one else in the office got close to the 18hours above either, but i guess YMMV...
Your watch was defective or you must have been using it quite heavily. I've been on this and other message boards discussing the Apple Watch since it hit the market, and my experience of having plenty of battery life after 18 hours is pretty typical. On the days i use Workout or talk on my watch I might be closer to 15 or 20 % by the end of the day. Otherwise it's more like 30-40%.