I am looking for a platform to host python web apps and GAE was one of the obvious candidates. The main thing that puts me off GAE is not pricing or poor python support or the fact that you cannot use a relational database in a reasonably sane way. No, the main thing is that I simply don't trust Google enough to use GAE. What if they decide to ditch GAE because it's not profitable enough? How dedicated to GAE are they right now? Sure, they introduce new features but compare to the competition they seems incredibly slow.

I've also looked at Heroku and although they are still working on fully supporting Python, they seem much more trustworthy. Heroku's main and only business is their hosting platform, they can only neglect it at their peril. And because of this, the focus and speed at which they deliver their product is amazing compared to GAE.

I didn't even bother to try out GAE when it was "free" but I would probably pay to use Heroku once Python becomes a first-class citizen. That's how exited I'm about their product.