I am a diehard S2000 fan and I have owned one until it became a financial burden for me (crazy high insurance... was paying $350/month). Anyway, I have driven various 370Z in the past including base+sport, same w/ mods, NISMO, and fully loaded vert. I absolutely love everything about the new Z except for one little thing... which keeps on turning me away from getting one: feel.
By "feel", I mean several components on the car: steering, accel, brake, and shifter.
When I had an 05 S2000, it was the last YM of S2000 that was sold without the newer drive-by-wire with various computer controlled technology including the TCS for the 06+ models. S2000s are by far the best car I have ever driven from the manufactures that give you a very direct feeling while you're in control of the car. EVERYTHING feels direct and linear. I have also driven quite a few 06+ S2000s including the CR, but they are actually not bad at all.
As for the new 370Zs, I feel that the car feels very "fake" or "indirect" should I say. The acceleration feels very smooth and straight, but the pedal feel is numb. Same goes for steering input, brake, and shift. I love the power of this car. I seriously do. It's so hard not to give in and buy one right now, but it's also hard to justify buying one new... or even a used one at $30+ for me when I can buy a AP2 V1 S2000s for nearly half of that price. Of course, the S2000s are aging and do not have any amenities that the newer Z offers, but for a pure driving purpose, I'd still go for a S. If I had the money to buy both, I'll keep the Z for daily purpose, and the S as my weekend toy..., but for now, I have a daily and it's called a G with 4 door so I'm very happy with what I have.
Just my 2c.