I always liked what Google was getting at with GAE i.e. a simpler, more cohesive AWS. But it just doesn't seem like Google has its heart in it. And we all know what happens to products like that at Google.
Do try to keep up: https://code.google.com/p/googleappengine/wiki/SdkReleaseNot...
So many new "me too" clouds, Azure, Rackspace, HP, even Oracle, and now Google.
Here is the run down on the runtime services available in the Java SDK (I think that it and Python are the most complete, not everything is available for Go last I checked): https://developers.google.com/appengine/docs/java/apis
This is a good supplement: https://developers.google.com/appengine/tools_tips
So queues and email are in, messaging might be served by Google Cloud Messaging or the recently announced Trello partnership. I don't think anything quite like CloudWatch or Route53 is available.
I think of GAE as more like Heroku + add-ons than a straight AWS competitor so I wouldn't expect them to be entirely equivalent. On the other hand more control over the runtime lets them offer things that are entirely out of scope for AWS (channels).
As far as updates, the blog shows the the SDK gets new features fairly frequently: http://googlecloudplatform.blogspot.com/
Yeah, I have no intention of using GAE, they don't support haskell anyways. GCE is the direct equivalent of EC2, they have an EBS and S3 equivalent as well. I that core puts them in a pretty direct competitor position.