Interfolio? and LORs questions.

I was wondering if anyone had used this service for their LORs? If so, have you had any problems with schools accepting your LORs from them?
What I’m trying to cut down on is the amount of paperwork for my recommendation writers. I figured one central service who will certify true copies to the schools would be nice, that way the writer only writes one and the service does the rest. Unfortunately, I’ve heard some schools choke at that.
Also, can anyone speak to whether or not you need to get new LORs should you have to apply again? Not that I’m planning on that happening, but you always cover your bases.

Dave - I can’t speak as to how some schools feel about the letter being written only once and distributed by Interfolio. However, I attend Ohio State, and they have us sign up for Interfolio to do our letters of recommendation. I wouldn’t think that a single letter written by the recommender would be a sticking point as many schools have a service where you create a central file and then they distribute your LOR’s as needed to the med schools. Many also do a single “committee” letter.
I have signed up for Interfolio and have found it to be fairly simple to use. I wouldn’t worry about going with Interfolio - if a school seems to balk at it, then you could just ask your LOR writers to write them a specific letter. Personally, if I was a recommender, I would be much happier about writing one letter (especially if I have lots of people I am writing letters for) than having to write a new letter for every institution applied to.