Neither buy a Mac.
He is concerned with the price of Windows and you tell him to buy a Mac?

zOdeac, Think out your software requirements for what you want to do with your cabinets.
Are you just going to run MAME?
You said you got guns, do you want to run PC gun games or just MAME gun games?
What front end do you want to use?
Do you want to run console emulators? If so, which run the games you want to play and have features you require?
What utilities do you need/want to use? Hardware configuration, front end extras, management, etc.
After you figure out what software you want you can decide which OS can handle it all.
Windows Easy setup easy update ROMs but take so long to boot up and its a memory hog not to say I wish to make 3 of this MAME games so ill have to buy 3 OSs = more $$$ witch sucks when your trying to help friends to.
See the
nLite thread in the software forum for info on stripping down Windows XP so it uses about 40MB of RAM and boots up in about 30 seconds.
Id prefers to make it more like my arcade so change the backgrounds and items but I just dont see it that well in the windows version. I guess I want to make it more locked down so Windows is not accessible with Dos I can do that. Not sure about Ubuntu.
See the
Hiding Windows section in the wiki. You could probably get the same result on linux but I'm not sure about that.