As I do bigger project using app engine, I see a few things,
One is, not all python module would work, so things like Python Imaging Library will not work. Which is useful for me to resize my pictures.
Two, app engine is flexible enough for me to choose the tools I use, which here I use dojo, quite freely. But also restrictive, because currently it is python, and revolve around big table, not all python module work.
three, would be nice if webapp, are able to automate a few task, like create form. But it also make it easy for me create the dojo upload form. Probably will try using django on app engine on my next project.
Actually really I have not much to complain, since, one I am to poor to get amazon service(I'm just a soon to be fresh grad), and too poor to get web hosting service with python on it.