As far as monitor, In a past life I used to own a computer store and actually have a few 17" CRT monitors laying around. How much of a pain is it to use one of those with a VGA converter? What are the drawbacks to doing that?
Well if you go with the 60-in-1 option, that board supports VGA output, so you can just plug the video feed straight into your Computer monitor and it should be good to go. You'd still have to wire the controls off the JAMMA edge, but that's easy stuff.
But CGA to VGA converters vary in quality and lag. You're dealing with upscaling the image, and while there are cheap converter options out there, most of the quality of those are sub-par and made from cheap chinese manufacturing. For instance the Gonbes GBS-8200, though cheap and available everywhere, introduces image degradation and display lag. Pretty much negating any point of going with original hardware. Lag is important to think about when having to deal with converters. It'll break the game play experience right away.
If you're going for the authenticity of real arcade boards, you should get a real arcade monitor. Introducing converters into the chain just adds another point of failure, and unless you shell out the bigger bucks on a proper upscaler, you're not going to get a truer experience than going with something like MAME.
Seriously though, if you have PC monitors readily available, and you want to go with dedicated hardware, going with something like a 60-in-1 and setting it to just play Ms.Pacman will not only save you a bunch of money, but the outcome will be pretty close to authentic. No one will really know, tbh.