I have one. Ive had it for over 2 years now. It is great. The face is large and the numbers are really easy to see when doing a workout or race. The face is a little bigger than old timex, but same or smaller than garmin faces, and easy to get used to. It also holds the history and tells you the date of the run then shows lap splits, overall time, etc.
As for sensitivity, there is a setting for that. Change it to Hard, then the laps wont automatically be taken. If you have it on the low or medium, then yes during normal running and bouncing, the laps will trigger.
The only time I have ever had an issue with inadvertent laps on the Hard setting is when a friend gave me a high five while running. That triggered it.
Overall for the price, that is a great watch. I paid $80 I think when it came out and that was worth it too.
One complaint I heard from a fellow runner was that he did not like the strap. And the strap can not be replaced. You have to get a new watch if you break the strap and you can not use an aftermarket strap. That said, I think it is comfortable and after 2 years, the strap still works well for me.