I use Weld for a side project, had hard time getting it to work with JRebel, and the redeployment is a headache, also hotswap didn't work for proxied classes (Injection / CDI). The JEE 6 stack, somewhat affected by Gavin King (author of Seam and Hibernate) is not that bad, it's just not that cool anymore, same way that Spring MVC is less cool (just because there are arguably easier and more rapid frameworks such as Play) and by saying less cool I mean less fun and less fun means to me less productive.