I have a 2001 which is basically the same bike with different colors.
The consensus is that they're pretty bullet-proof so I wouldn't be too concerned with the mileage unless serious mods were done or there is evidence of abuse/neglect. That should be clear with a visual inspection + test drive.
I wanted a bike that is cheap/easy to maintain, and can do it all: commute, highways, twisties, offroad. I wasn't concerned about 2-up or long trips, which would most likely be uncomfortable. I was also looking for a DRZ400 (my first choice) but couldn't find a good deal at the time.
I love the bike and am real happy with it. I can see myself keeping it for years and doing some mods here and there to keep things interesting. The KLR650, DRZ400, and XR650L are all more popular than the DR though, so the general opinion is that those are better bikes. I've never ridden the KLR but based on the weight alone I would not consider it for what I want, and the XR is just way too tall for me (30'' inseam).
Any specific questions/concerns?