We have bought a fair number of machines from Namco since there is a Namco owned arcade near us.
The games listed for sale on the website are generally machines currently in Namco owned locations. Prices are set by corporate on a per-title basis, condition of any specific machine isn't usually factored in.
The pro's are that these are usually more recent titles than what we typically see and pricing is usually very fair, sometimes darn cheap.
The con's are that there is no price haggling since pricing is set by the higher ups and machine condition can vary from minty to trashed and you never know until you get there.
From my experience, games out of Namco arcades typically have pretty good cab and over all look nice. I seem to run about 50/50 with monitors in them, some are great, some are begging for caps and some have weak tubes (these machines ran 24/7 in some locations). Namco doesn't dispatch techs to any of it's locations on a whim, so sometimes the games are sort of hacked by local management to keep them running. In a nutshell, these games are usually a pretty good deal, expect some tinkering, keep an open mind about the monitor and enjoy!
D