Hidden limitations of Google App Engine?
I've been looking into writing a web app that will run on Google App Engine, but before I commit myself to the platform I'd like to know what, if any, limitations there are. I'm aware of the basic CPU/bandwidth restrictions that Google places on the free service, but I'm wondering more about development restrictions like how BigTable compares to a standard relational database and what Python libraries aren't available on the GAE platform (and what alternatives Google provides).

Basically I'm looking for any hidden roadblocks before I commit to the platform. Thanks for your help!
Hidden limitations of Google App Engine?
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I've been looking into writing a web app that will run on Google App Engine, but before I commit myself to the platform I'd like to know what, if any, limitations there are. I'm aware of the basic CPU/bandwidth restrictions that Google places on the free service, but I'm wondering more about development restrictions like how BigTable compares to a standard relational database and what Python libraries aren't available on the GAE platform (and what alternatives Google provides).

Basically I'm looking for any hidden roadblocks before I commit to the platform. Thanks for your help!