The tale of a hosting migration that shaved 40% off response times
We had a positive experience moving Cult Cosmetics, a rails app, from Heroku to OpsWorks, with response times reduced by ~40%. If you're thinking about making this move, DO IT, but realize that it will probably require more time & effort than you expected.
Why ditch Heroku?
I'm sure everyone has their own reasons, but here . . .