Those aren't really alternatives to GAE IMO unless you would also say that a laptop is an alternative. A real GAE alternative would be a hosted solution that doesn't require you to install an OS or even know what OS it's using.
I'm not saying "Don't use GAE because it's expensive/google/whatever". I'm saying "Don't use GAE or anything like it".
Cloud Foundry gives you the "just push" experience for both of these (as well as vSphere, OpenStack, GCP and more to come). It's open source, with the IP owned by an independent foundation.
Disclosure: I work for Pivotal, we donate the majority of engineering on Cloud Foundry.