I originally wanted the AES, which seems too prohibitive concerning actual carts, then the CDZ as a medium ground....but I think I might pick up this moderately priced Time Harvest unit....(unless there is some documented hate for it) ---as the website for the Jamma X implied that it would be a couple years before new orders would be processed--- and a few MVS carts to hold me until I can afford the NeoSD.
It is my understanding that the unibios should allow me to play the carts as AES (?) which I hope is the case.
I've had a Neo-Geo CD for a long time but bit the bullet on the Time Harvest CMVS back in the spring. I honestly love it. I should mention that after a few months, I did have some voltage issues. I sent the unit to a forum user and it works great now. I had to wait about a month for him to actually build the thing but he shipped it from China to the US in something around three days.
As of now, I only have two MVS carts: Real Bout Special and the 161 in 1. Honestly, the only I time I've used the Neo Geo CD since having the CMVS is while the CMVS was getting repaired. That, and maybe a couple times to play a couple games that aren't on the 161 in 1 (i.e. Magician Lord and Windjammers). I'd say take a look at what's on that cart, and if it has almost everything you want, go the CMVS route. If not, go with a Neo Geo CD.
Also, I might've missed if you said you wanted to play fighting games, but like others have said, the load times can be a pain (especially with the KOF games where it's between every round). Everything else loads of really fast for the most part. I haven't played a fighting game on the CD since I got the CMVS.
One final note, the Time Harvest CMVS does NOT have a save battery of any sort, so if you want to play four stages of a game and play the last ones later, you need to leave the system on. Most games are so short that this doesn't bother me but if saves are a must, get a CD or a different CMVS.