I've been reading up on GAE+Django and it doesn't seem to support RDMBs or installation of libraries. Has this hindered you in your coding?
The project you are working on should determine the technology stack, for most things I prefer GAE instead of EC2 (I have projects on both). Feel free to use my template/example from github.
https://github.com/mcotton/GAE-template https://github.com/mcotton/GAE-blog