I'm having this debate with myself right now. I'm building a MAME cab for a friend. He is not a real gamer, more of a guy with cash who likes toys. I have an Avga and JPAC, and P800 system on hand. It would take a good amount of work to build him a real mame system, once you add in software configuration, power management, the PC speaker issue, etc etc...
...or, I could just snag him a 300 in 1 board and plug that sucker in in 5 minutes.