I learned Python on App Engine. After a couple of projects I got paranoid about "lock in" so I rented some server space and learned vanilla Django and did a few projects. Only then did I learn to appreciate App Engine.
Fast forward a couple of years, whenever I need a server for a mobile/desktop app I'm building I use App Engine. For many things, especially if you're just starting out, you can't beat App Engine's ease of use and cost.
I have been programming for last 8 year, however, both python as well as app-engine was new for me. Below after few posts i have written how i learn python so i dont want to repeat here. However, i think python on app engine is boon for python beginner like me. Since i have worked on cake-php and ruby on rails i found webapp also somehow similar. My website www.lolzwow.com is live and getting good number of hits, however, i don't have to pay a penny and statistics shows that free quota can handle still more traffic than what i am getting now. So, python app-engine is a good gift from google to python community. Thanks Google
Fast forward a couple of years, whenever I need a server for a mobile/desktop app I'm building I use App Engine. For many things, especially if you're just starting out, you can't beat App Engine's ease of use and cost.