Before you go down the AES route, I'd try to figure out how much the games you really want go for. When I got into Neo collecting I was originally looking at an AES, but after realizing how huge the price difference was between the home and arcade carts I went down the MVS route instead. The very early Neo Geo games on the AES aren't generally that expensive, but games can get pretty astronomical. Especially if you want a copy of Metal Slug. That was almost the singular reason my interest in getting a home console died immediately.
I really have no idea what the current AES market is like, but I imported an MVS copy of Windjammers from Japan for a little more than a hundred USD. I'd recommend signing up at the Neo Geo forums if you have questions.