I have not been able to find a good solution to having a personal vibrating timer with me.
Requirements:
Easy to set so no frictional cost to starting a pomodoro for instance. Does not beep. Keeps vibrating until silenced rather than vibrating once and then stopping (I don't notice these).
Pebble has a timer app that meets all your requirements. I use it for pomodoros, laundry, steeping tea, cooking rice, etc. Unbelievably handy.
I think that pushes me over the edge on pebble. Thanks!