I've been using a GQ-4X from MCUMall: http://www.mcumall.com/comersus/store/comersus_viewItem.asp?idProduct=4282
For pinball, it has done everything I've needed it to do. I've also gotten pretty good support on their forums when I have a question. If you have to do some obscure stuff for arcade games, you may need to buy something more expensive.
Since this is most likely for your employer then I highly recommend the Superpro 3000u. My only complaint is it doesn't support a 64bit OS. Other than that the software interface is excellent and I have yet to be screwed by this machine in well over 200+ burns. She's rock solid.
FWIW I recommend you stay clear the hell away from that cheap Jap crap on eBay. They generally don't send with software and then you'll be back here asking where to get the software. I've used several of them and they flat out suck. My .02