For the MV1, MV1F, MV1FS, MV1T; if you find them clean with no battery leakage then go for it. Snip that battery and replace with either a coincell or a new rechargeable. They are good boards since they have controller ports on them, personally I'd go for the ones with the newer chipsets (All except MV1 (Large)).
MV1C, it's a great board but lately I've been seeing ones on ebay are corroded or heavily rusted. Keep in mind that this mobo 3 custom chips that take the place of 5+ custom chips on other MVS boards so if ANY of them have rusted legs then the only fix is a chip swap and that is assuming the pads aren't rusted, too.
The FZ, FZS and 1A. Stay away from them if you plan to consolize them unless you fully test the board with a Diagnostic Bios. 8/10 of them will have Z80 errors and if it isn't a Z80 error then it's a palette RAM error, BRAM error, sometimes all three. The solder mask on them is also pretty thin so any slight corrosion is enough to cause problems.
