I also have an app on GAE. http://www.tubesmix.com
Right now there's no charge as there's only a couple hundred users and the resources used are low.
But this change worries me a lot. Even more so since all my backend code is tied to GAE infrastructure. This is very disappointing coming from Google. Since when did they become so nickel-and-dimey?!
See for yourself. Sign up for the limited beta and you'll get an invite. http://www.strobecorp.com/products-platform/
Or if you're on twitter, hit me at @allad. I've got some invites left.
The Linux kernel is on Git. Thousands highly skilled developers use it to manage one of the biggest software projects in the world. That's how mature a technology git is.