I currently have a Grails application I\'m evaluating to port to Google App Engine and I\'d like to know experiences regarding:
You may also be interested in Gaelyk (http://gaelyk.appspot.com/) Gaelyk is a lightweight wrapper which enables you to deploy applications written in Groovy to the App Engine.
Gaelyk offers a lot of the advantages of Grails including:
(although it doesn't include internationalisation, CRUD scaffolding or a HQL type query wrapper)
As it is more lightweight it doesn't have the performance issues on App Engine that Grails does and now that you can reserve instances http://code.google.com/appengine/docs/adminconsole/instances.html#Always_On it is possible to remove the startup time problems!