I had the same issue (fork comp screws) on my first (02) gen 1. Was the first thing I checked as soon as I was out of sight of the dealer's when I test rode my current one (54). Take a flat screwdriver with you when you go to see it. But yes, they don't really do much anyway! Suspension is probably the only thing that lets down one of the best all-rounders you can get. Being a cheapskate, I just went for a Hyperpro respring front and rear, which helped, but is no substitute for a proper revalve on the front and a Maxton/K-Tech/Nitron shock, so I'm told.
When buying, one tip is to check for vertical play in the swingarm (bike on centre stand, lift rear wheel). About 1mm of play is actually within spec but lots of people don't realise this so you can bargain to get some £ knocked off, or if in a dealer, get the bearings and linkages repacked, which will need doing anyway at some point.
The engines go on for ever if you change your oil regularly. Stripping and greasing the EXUP should be done at least once a year. Make sure the EXUP valve works (and bolts aren't seized) before you part with any cash. It has been known for people to remove the pulley and flog the bike with a stuck valve.
Apart from that, nothing much to watch out for really, except the same as when buying any other bike.
Oh, and it's worth mentioning that I've just hit 30,000 miles on my 54 plater on the original chain and sprockets, due to using a Scottoiler. Replaced with DID ZVM and JT sprockets for £170 fitted.