I would say that it all depends on the monitor. The monitor size, quality, and condition are more important than anything like joysticks or what games are in it since those can be had for cheap.
If its a burt-in bubbly 17" screen, I'd say $200 or so. If its an immaculate 21" with no burn in, maybe $400.
It would also matter, at least to me, if it was an actual SNK USA MVS (with red MVS sides, coin counter, light-up switching marquee, etc) or just an old Berserk machine with an MVS slapped in it.