I have worked on a few Ducati's, 900 monstro, 916, Paso, I own a 97 900SSCR that I like a lot. The first thing you need to do is establish that the bike hasn't been abused and that the maitenance schedule has been followed. Also make sure you have a Ducati dealership nearby and that they have qualified mechanic. Ask them how long it takes to get parts. Ducati built a new factory about 3-4 years ago and that made quality better and parts easier to get. I know we had a really hard time getting parts, but we weren't a Duck dealer. Brembo brake parts can be hard to come by as well. Does the 600 have the desmodradic valve system? If it does set up a schedule with your mechanic and stick with it, you don't want problems with desmo system. If you live at altitude make sure your fuel system is set up for that.
If you get a good bike, and stay on top of it, it should serve you well. Ducks are different from any other bike, and that is why I like them. They are not as bullet proof as Japanese bikes, but if taken care of they do pretty well. They aren't like every other machine you see out there. Suzuki and Honda both make Ducati look alike bikes, that you should tell you something. The drive train sounds like nothing else and the brakes are superb. Some El Monstro's had the dry clutch, which takes some getting used to hearing. The 916 dominated the super bike class for quite a while which is really amazing. Ducati is a fairly small company, and knocking off the huge Japanese companies, the Italians and Harley Davidson racing (when their bike actually ran the full race) is pretty impressive.
Quick Story - Don't know if this is true, a Triumph dealer told me this. Aprillia, which owns most Italian motorcycle companies (laverda, guzzi, gas gas, bimota) tried to buy Ducati. The employees found out and threw gasoline all over the factory and threatened to burn it down if they sold the company. Aprillia backed off. Don't know if that is true or not, but it is a great story.
Once more, don't get off the maintenance schedule.
