Yeah, keep tabs on the best prices and keep both formats...hell, even get the Neo CD if you're thinking about it.
I did party with my AES and games, jumped on the MVS hardware and haven't looked back although sometimes I wouldn't mind having an AES all over again with sweet cheapies, Samsho II and Fatal Fury Special are the best games for the system and prolly the cheapest ones too. My problem with the AES is the lack of options at less you modify it and it isn't cheap so you mind as well modify a motherboard and get the most out of it. The nice thing about the AES is the packaging, nothing more, the CMVS will give you that same thrill of playing the games with the same peripherals and all and if you play legit MVS carts then you're not missing absolutely anything, however some people like the console just for the prestige...pretty lame if you ask me.
MVS will always edge out the AES for me, but that's a very personal thing for me, I like to thinker thus I made my own CMVS, I like to take things apart, I love editing in PS, I like to build things, it just works for me the best as the CMVS world and MVS in general requires you to be a bit more hands on than the AES world ever could. I would however wouldn't say no to a fully loaded modified AES for the right price, then I'd just buy a few cheapies and spoil myself every now and then if the right situation presents itself, as for MVS I'm all done, got all the games I always wanted and then some.
MVS4LF
Let's look at it from the nostalgia shades though. There are 2 possible scenarios here and they both depend on your first experience with the Neo.
MVS
Like myself, if you learned about the Neo and SNK through the arcades then you know this was the ultimate most amazing thing to have, a nice MVS arcade at home...maybe that SamshoII kit with the swords and such...OMG...amazing, anyway, MVS was just the best thing out there, I always wanted a cab when I was a kid, pretty much the reason I got the AES to begin with.
AES
Others found out about the Neo through retail shops and magazines. That's cool too although you don't get to experience the real thing 'cause there wasn't a demo, people wanted it 'cause it looked awesome and the price tag was so crazy that it made you curious.
Either of those 2 scenarios are cool and all but I feel most people that get a Neo now do it 'cause they can afford it, which is great and all but that's just the same old "prestige" thing. I for one can't care less about filling that void but if that's your thing, hey go nuts...
The best route overall is to get a real nice supergun, get a MVS board get a Uni Bios, a couple of SNK Neo peripherals and you're all set, best of everything at your fingertips, then if you decide to jump forward with arcade hardware you're ready to go.
MVS is like a gateway drug to arcade hardware...once you realize how attainable and easy it is to deal with you're gonna jump in that rabbit hole like there's no tomorrow.
MVS, CPS2, PGM, Atomiswave, etc. All easy carts systems to work with for any given supergun and then if you want you could get into PCBs as well...talk about crazy then 'cause there's just so much, also some Multiboards are worth the money just for shits and giggles...