I paid less than $200 (dollars, not pounds) for my CMVS. It came with the UniBIOS, a Neo CD pad, and an AES stick. I have Rage of Dragons, KOF 2003, Metal Slug 3, and many other games, none of which cost me more than $45 except Pulstar which was over a hundred.
To do that AES style I'd need thousands...PER GAME in many instances. If you can actually source one of those £200 converters you'd have...nothing...since all it does is let you play MVS carts...and an MVS can already play MVS carts natively, you still be at step 1 before you even talk about a system.
The AES is probably the most clear cut example of a more expensive alternative that is worse in every single way. If you're more interested in hype than game play, that is, if you are a poseur, then AES is great. Me, I like flying spaceships and shooting fireballs and shit.