I REALLY like mine. I've had it for over 15 years and it's my favorite out of the 10 or so bikes I own. I lean it hard in the corners and it's never given me much trouble.
I cant think of anything off the top of my head to look for aside from the usual (running condition, electric condition, compression, etc). You'll get a BIG plus if you have side covers...they are the first thing to fly off / shatter on these bikes. Also, if the bike has power, turn it on and wiggle the connection beneath the turn key (where the pigtail goes in). The connections in the turn key get weak over time...if the lights blink of the bike shuts off you will need to get a new key switch.