hi Andy u do get the added advantage of reduced lag when using groovymame
by the way if u didnt know, mameuifx also uses the soundsync patch if u wanted to use that instead of cabmame (which as you already found out, is out of date now).
ps. when using mameuifx soundsync it works best under a certain configuration (ie. u need to use direct3d not directdraw for one thing, otherwise it doesnt work right). i can dig out the details if it's something u are interested in anyway.