On the contrary with other pythonic frmeworks, the curve is not that difficult. Currently we are using the combo of cherrypy and dejavu in python, and the learning curve was surprisingly small.
We're using sqlalchemy here and it's been nearly painless so far. It scores on maturity (despite the 0.5 version number), great documentation and a very active and friendly community. The learning curve is steep (as with any ORM) but very rewarding because the pieces constantly fall into place. Everyday tasks are idiomatic and syntactically sane, plus even complex joins and subqueries can be constructed using the standard building blocks. So far we have not run into any limitations, unlike with the django ORM which gave us constant headache at some point. The latter really feels like a toy when you have tasted the real thing.
Anyone who tried hands with sqlachemy or storm ?