Depends on what you meen "better." Better all around, better sq while still getting loud, or over all loudest? I think the Brahma would have the best sq, and the mt would maybe be the loudest, but it would sound kinda bad. The x.x.x. is very very good too.
The x.x.x.? I think it has more spl than the brahma. I know the mt is not what you want if you still want good sq. I'm not sure between the other two though, you'll have to wait for Jonathan to answer that.
MT isn't a daily driver sub. Comes with no warranty and is designed strictly for SPL. Thermal power ratings and linearity don't apply. X.X.X. would hit harder than a Brahma, I actually like the X.X.X. better overall SQ and SPL, but it's always subjective.