I've had some problems recently with my chain coming off the big ring when trying to do PowerStarts in a 50/13-14 or so combo. Finally decided, after noticing that some teeth on the ring looked like some metal was shaved off, to get a new 50t ring, cassette & chain. I'm full SRAM now. No Shimano on the bike now.
Anyways, I put this stuff on last night and planned on doing a zone 2 ride this evening. Figured that I would also try some PowerStarts to see if the chain came off. !!W00t!!! This fixed it! I was able to do them in the 50/13 combo. Yay!! If it doesn't rain Saturday, I'm going to try to do them again, but in a slightly easier gear - 50/15, so that I can get the cadence up to 95+. I am thrilled!!