[litewulf]

I do (but I'm not sure I can talk numbers.)

Honestly: I like that it means I don't have to muck around with configurations, the fact that downtime is out of my control is frustrating, but at the same time, if I were running things, there would be more downtime due to mistakes I/my fellow developers make. Datastore latency is something of a painpoint, but it was something we knew going in and designed a bit for, and it also helps quite a bit that we're very read heavy in the ways that appengine wants you to be.

My friends at wolfire ran the humble indie bundle (and lots of other stuff like their blog as well), and it does well. (documented at http://googleappengine.blogspot.com/2010/06/how-app-engine-s...)