We are having amusing problems with appengine. For example they provide no way to limit the number of instances they decide to start. If for example you run out of datastore i/o capacity (it doesn't scale with how much you pay) they will quite happily start more instances even though they won't help in any way, and actually make things worse.

We switched to premier which supposedly gets us all sorts of extra stuff, but for some bizarre reason will no longer show your daily charge breakdowns.