is that right that the mv only has 16 bit ?
Yep! I believe there was something strange bout the USB too on the MV but can't remeber what it was.
MV-8000 can have max 8 out (with the 6-output expansion option).
MV8-OP1 expansion card, users gain six additional analog outputs, a digital input, plus an R-BUS port that can be used to transfer up to eight channels of digital audio to R-BUS equipped V-Studios, or to ADAT-compatible devices using the optional DIF-AT Interface Box.
The mpc4k on the other hand can be expanded with both 8 ADAT in/out, 8 analogue out and S/PDIF in/out making it a more powerful machine.
MV-8000 has a reverb, a chorus and a MFX-block.
MPC4k has four individual fx blocks with alotta fx.
I have a fantom-s61 and must say that the pads are CRAP! Dunno though if they are the same on the MV8000.