I'm in the middle of configuring and choosing my architecture components for my GWT based we application. I have to choose a simple way to persist my data model on the target server which is **Google-App-Engine**.

Contestants:

* **Spring Roo**: I've tried this and integrated it in my project and it's pretty nice. Seem to be simple to use and the java AspectJ ITD seem a very cool tech to assist me in generating and persisting my entities. For now it only works with JPA so, not really exploiting DataStore real potential (RDBMS only :(
* **Objectify**: Not tried this one yet but it seems great to address directly the Google DataStore API. No fuzzle with JDO. I checked sample usage and it looks very nice too.

Does any experienced guy has an opinion?

Thank you!