ec2 versus engineyard, clarrifications

Can someone clarify for me what advantage engineyard provides over running ec2 yourself?

Is it that they provide chef recipes, automate backup/restore scripts for you via a web dashboard? Or is there something more to it?

i.e. if I have puppet scripts to create a server, and have backup/restore scripts for my db etc. does engineyard still provide more services?

I assume you're talking about their ec2 based product, not the xcloud
stuff.
You're also getting their stack, one would hope they've got all the
various bits (database server versions, load balancers etc.) playing
together nicely

Another large part of what you are paying for is support.

Fred