I personally have gone for EC2 and intend to stick with them for now due to the support received and what I've been able to achieve using it. We've tried Google

I personally have gone for EC2 and intend to stick with them for now due to the support received and what I've been able to achieve using it. We've tried Google App Engine also (we're mainly Python guys) but that was my first concern that if I became too comfortable with it that we would be locked in. Ultimately though the decision was made for us - Google didn't allow some of the libraries that we need to use