I liked my V-spec but the case started to split. They may have fixed this but just throwing a little buyer beware out there.
The Ninja engine is pretty similar I believe but it's just a 5 port instead of a 3 and doesn't have the problems that O.S. does. That's just what I've heard anyway... I was going to buy a ninja till I got the Werks B5 engine. Love that thing.