Yes, I was wondering about the very same things.
What do you get using the MVCSoft CMP plugin?
I can't really tell you about MVCSoft's PM; you will have to check with there site. I can tell you about JBossCMP, as I wrote it.
JAWS is the persistence manager in JBoss 2.x, and JBossCMP is a completely new persistence manager for 3.0 which supports CMP 2.0. From what I understand MVCSoft is targeting those that want to write cross server platform applications (they support many platforms).
My goal with JBossCMP fastest, most reliable, and easiest to develop with persistence manager out there. This means that there may be some features we won't have because they are directly opposite to the goal. For example I don't plan on supporting polymorphic entity bean database mappings, and they are hard to work with, slow and just a dumb idea.
As for a feature road map, I don't have one beyond the next two features (plugable autonumber generation factory, and optimistic locking strategies).
I'm always open to feature requests.