membrane sweep?

So I was at my dr today for my weekly appointment. She said cervix is soft and I am about 1 cm dialated (about the same as last week) She suggested that maybe next week we will do a membrane sweep. This is my second child and I never had one with my last. Ive heard it can be a little uncomfortable. Anyone have any opinions/experience on whether it works or not? How long after you had one did labor start?