I don't, but have often wondered about its utility in my life. I would be interested to hear your thoughts on it.
On a side note I have a co-worker with an iWatch who often takes long trips to the bathroom, presumably to avoid work. I've thought about texting her phone and telling her to get out of the bathroom knowing full well a text message would appear on her watch. I haven't done it yet, but one day.
After owning it for a whole week I like it. It has a pedometer heart monitor I can receive texts and calls can reply to text with text to speech has navigation and I can modify my watch face to anything I want. Well worth the money.