That place does not have many arcade machines in stock. AFAIK what they do is take orders from people for a machine they are looking for, then try and source one from somewhere - collectors forums, ebay etc. IF they eventually find one then they stick about 500% markup on it and then sell it on to the person who requested it (probably long after they have taken a deposit large enough to buy it and ship it to them in the first place).
I am a video game collector, just signed up here in the hope of finding an old classic fruit machine for my games room. I have a nice, working fully original Paperboy (pretty hard to come by). I bought it 10 years ago and have seen only a couple sold since in the UK....the last one of these was crazy expensive - something like £850. I paid much less for mine, but there's no way that I'd sell it for that now!!
MAME cabinets are OK for what they are, though places that sell them online tend to take this piss on these also. Some games which require dedicated controls though, such as Paperboy, you really need the original cabinet to play them authentically.