I heard a lot of good things about Scala and the Lift Web framework recently, especially from Foursquare\'s guys hence, I might use this technology in my next projects.
I'm developing enterprise financial application in Lift for more than 6 months and I was JAVA programmer former. I have noticed a few points, which could help you:
I write noticeable less lines of codes (great example)
Around Lift there is strong a very kindly community. They always try to provide a substantive answer. I haven't any bad experience. Even they are open for new suggestions for new features in Lift. They approved two of my suggestions!
New stable minor version of Lift is announced about every 6 - 8 weeks. New milestone is regular every two weeks.
Lift is great framework for web applications. You can read about seven main features of Lift.
Lift default ORM module - Mapper is not for big and advanced database models with lot of foreign keys and constraints. We had to use Squeryl.
I can't imagine that I have to return to JAVA code now. But my little advice is to try to code some simple application and you will see.