Hmm, I really liked what I saw in Seam, especially the fact that there are so few files in an app :) Basically, I have the view that one big advantage of Rails is that it controls the whole application stack and that is kind of what Seam tried to do as well. So that's the good part.
The bad part is that the application scaffolding does not work as advertised. OK, it's beta, so that's forgivable. But if you look into the Seam forum you find that many people have problems even with the scaffolding example when they try to use their own db's. There is help given in the forum but overall I was a bit put off at this point.
Back to AppFuse I was again shocked just how much code is there already in an essentially empty starter application. So I had to get over that, adjust my mindset not to think about Rails and off I went. I was not very productive, but I got my stuff done in the end (Matt has really done a great job with AppFuse IMO). I guess Spring, Hibernate, etc can be considered outdated, but they work and there is plenty of material, help and tutorials around. And that helped my productivity quite a bit as well.
In case you should try to follow the Seam application scaffolding example take this hint: the Hibernate reverse engineering tool when applied to a medium sized Oracle db is so slow that you will assume it has crashed. Chances are that it has not. In my setup it took around 20 mins to come up with a list of tables. Apart from this abysmal performance on Oracle I like the tool, actually.