Well, the title says it all. I've moved dnstwister to Heroku.
It didn't take a lot of work and the benefits are huge - the killer for me was the ability to control exactly how much the application scaled up cost-wise. The costing for hobbyist use on Google App Engine was, in my opinion, completely unmanageable. You couldn't limit the performance of your app under load, the only option was to just pay more and more until you covered the quota exhaustion. With Heroku if I get a surge in interest it'll just get a bit slower, and I can choose to scale up at that point as necessary.
I also like deploying through pushing a branch to GitHub and the whole admin dashboard interface is really slick.
Bookmarked report links will automatically redirect from the old domain so you shouldn't feel a thing and the performance is right on par with Google App Engine.
Enjoy!
