I am--was--an EY customer as well for some time, about a year, and had been following it since its inception, particularly through a friend who was a customer while it was still in beta.
1. I haven't seen any significant changes to their product, except for the CLI tool as a replacement for capistrano. The CLI tool is a great improvement, but it's still basically a glorified capistrano tool, and doesn't even get close to comparing to the Heroku command-line tool. Predominately, I feel like the product has been stagnant. Support for Ruby 1.9 and Rubinius (currently in beta) is the most exciting thing I've seen lately. It's surprising rbx has taken so long when it's an EY sponsored project!
Part of the challenge with a product like AppCloud is there is no obvious way to update the stack without disturbing applications, but I'd still have liked a way to potentially update our base software (libraries and such) to something more current.
2. I'm so-so on this. Heroku support is free, but is not 24/7 unless you are a very large customer with a support contract. We paid for support, and EY support was sometimes helpful, sometimes not.
3. I'm not talking about objective comparisons here, these are "shots across the bow" so to speak. I know the pros and cons of both services very well, but what I am talking about are "subtle jabs" about how Heroku is not production-ready/capable, etc.
1. The platform has evolved in a nice, iterative way with no interruptions to my service.
2. Even without a support plan, they have some of the best people in the world answering questions in the forums.
3. I'm happy to see competition in this space, and I don't begrudge anyone from pointing out their relative advantages over their competitors.