Their product and support is excellent for companies without devops experience.
They promised me that I could stay on a grandfathered plan, but then changed their mind and are trying to force me onto a newer plan that is 300% more expensive.
They also suggested I could bring my own Amazon EC2 credentials and realize some savings by reserving Amazon instances. Then after a month of dithering and non-response, they told me they don't want to offer that feature anymore. Still haven't received a decision from them after a month an a half. Very frustrating.
Get your terms of service in writing (especially the fees and contract length). They've made promises to me on the phone that they later reneged on.
Engine Yard lets us focus on building our app, and leaves the DevOps worries to their platform.