Do some searches on here, MOTU's reliability is apparently AWFUL (hell, there's even a thread called "looks like I'm on my 3rd MOTU"), and furthermore, while the converter chips themselves might be the same as RME's, I'm pretty certain the analog circuitry surrounding it is inferior, and more importantly (for me), MOTU's PC drivers apparently are pretty crappy. I've been going through quite a debate on this myself, but I settled on the FF400.