We treat all author support issues to hello@leanpub.com as confidential, of course. For author support issues which are fine to discuss in public, you can see our author forum at https://community.leanpub.com/c/authors ... If you look there, you can see a representative sample of the issues people have had recently. (I don't want to turn this HN thread into a Leanpub author support forum thread, of course! However, our authors typically seem pretty happy with our service...)
i dont wanna air their dirty laundry but go try them out and if you like them then great. they certainly seem to work for most people. they struggled greatly with my 500 page book and after about 6 hours of wrestling with it i just gave up.