I have a lot of experience with Parse. What are you considering building? There are definitely some gaps in the product, particularly a sane job scheduler. I also found it tricky to deal with the relatively short timeouts, which ate a lot of our cycles to track down and work around.

Unfortunately my next few projects won't be built on Parse, which is too bad because I know and really like the team, and think there should be something a little more abstracted than Heroku for building a backend service.