We, streak.com, use GAE. We think its one of the best platform decisions we've made. Zero admin time, scales without us worrying about it, etc.
We aren't really worried about the platform lockin (we think it will be hard to migrate from any provider to any other provider anyways). Cost can be an issue if you don't optimize or do things the appengine way. But at least you have the decision - you can tradeoff $ for engineering time.
We aren't really worried about the platform lockin (we think it will be hard to migrate from any provider to any other provider anyways). Cost can be an issue if you don't optimize or do things the appengine way. But at least you have the decision - you can tradeoff $ for engineering time.