I've never owned one of these so I don't know comprehensively but it almost certainly you will at least need to find out whether he is selling a copy of City Navigator v9 (or any version) as according to some recent news:
http://www.motorcycle-navigation.net...sted=1#post186
You my no longer be able to buy the software yourself after the fact (Or at least until Garmin come out with version 10 next year)
If he hasn't got European Software for it, make very sure that you can get some from somewhere before you buy it otherwise you won't be able to use it (it comes with a base map, but it's a really low level of detail (no matter what Garmin say)), so be careful
If you can get the software then no problem, but budget that into the price (I think it will cost you about 150-200 Euros)
HTH,
David