For those of you tracking Seam 3 releases and bug fixes, you might have seen SEAM-99 was fixed with Seam 3.1.0.CR1 we released last week. I just discovered a small gotcha when using non-JTA transactions. If you are, your EntityManager must not be scoped @ConversationScoped or it will fail on every request.
We prefer JTA and hope the majority of our users do as well, but some may choose to simply use transactions from the EntityManager, which is fine too. Just be aware of that little gotcha if you are not using JTA.