just to chime in from the mac camp, ive built 4 macmame cabs and while they may not be the end all be all that a peecee could do, the old 300mhz powerpc macs were free and run macmame .57 on os8.6 just perfect, i havent had any problems. evn some of hte newer games run fine and the classics are perfect!
but i will admit if i had the time i would prolly go with a peecee just so i could have a front end.....