You must have been away for a while or something, because this has been a pretty big topic of discussion here on the forums.

The short of it is that the MM will run the Neu motors, but most (if not all) are experiencing cogging with the combination. The problem ranges from tolerable to not being able to get the vehicle moving without giving it a push.

Castle is supposed to be releasing a software fix for the problem, but it has been a long time coming. The quickest solution is to either get a Quark Monter Pro to run with the Neu, or get a Lehner to run with the MM.