Were you taken for a test-ride in a used pre-2004 S2000 (AP1) or a 2004 or later AP2? As others have said, the earlier models were under-tired and over-suspended. The 2004+ models have had the suspension "softened" and the tires widened. While some pre-2004 S2000 owners will tell you that the later cars are soft, reality shows quite a different picture.
The newer cars are slightly more compliant on the road, easier to manage on the edge, all while being faster than the older S2000s. Much to the chagrin of other drivers, I routinely bring out the tail of my S2000 and can easily control it at the limit...because I know what to expect (autocross helps here). Remember, these cars don't have traction control, so it is totally up to you to drive safely at the limit and in adverse conditions. If you can't handle that, don't get an S2000.
That said, I've only unintentionally spun my car once. I came off some wet pavement (because of sprinklers in a median) and made a hard left at about 45 mph. My tires were still wet and slipped on the dry pavement like they were lubed up with Vaseline. I was lucky not to eat a curb when it happened. If you stay sane while driving an S2000, you'll never have a problem. Of course, it's hard to stay sane above 6,000 rpm.
FYI, it's also a very safe car in terms of crash ratings, thanks to the stiff structure and high door sills:
I truly can't recommend this car highly enough. Realize, it's not for everybody though.
Modified by Jordi at 2:58 PM 7-15-2005