I think to many people, an emulator is "good enough". I don't know why, but it just never has been good enough for me. Maybe it's the slight latencies between the controller and the display, or the display and the sound, or the occasional jerk of animation... I don't know. But there's no way I would ever use an emulator in place of my Neo Geo AES. Similarly, I don't use UAE unless there's a good reason to - I always use my real Miggies where I can... and emulator just
isn't the same.
The best option is to find a Neo Geo arcade machine somewhere (there are still some around if you look hard enough!) and imagine having it in your home.

Over the years I've spent much more money on my Neo Geo than I'd like my wife to know about ( before I met her

) as I used to have more of the folding stuff that I could spend. But even now, I don't regret buying those games that I did, and they weren't all cheap. I still like a good Metal Slug session with my MS 3, 4 or 5 carts, and there's nothing quite like the true original NeoGeo versions. Last Resort is an excellent shooter - another of my favourites - and games like Sengoku III are still very entertaining.
Is it just a psychological thing? Quite possibly. But the important thing is that the enjoyment I get from it is real.
Incidentally, anyone with a NeoGeo AES should get a Universe BIOS. This lets you play the games in Japanese (with red blood but Japanese text) or American (fake blood but English text), and also lets you pretend to the cartridge that your AES is an MVS (the arcade machine) - all NeoGeo carts are the same, they read your console to find out what kind of machine it is, and the Universe BIOS lets you change these, and put in pokes for infinite lives and stuff. Very cool.