Well I have owned both. I had a 99 Monte Carlo Blue (or as my finacee calls its Bling Bling Blue!) NSX-T and I replaced it with a 2001 Silver 996 TT. Each was/is a daily driver.
NSX T
Pros: Shift Quality, Great Clutch, Build Quality, Front Visibility, Throttle Response, Very Nimble, Utterly Reliable, Gas Mileage, Interior Layout - Simple, But Effective, Engine...nothing like that redline!, Great Dealers, Looks, Price, Driver Feedback.
Con's: Braking, Ride Quality, Chassis Stiffness On The T's, Tire Wear And Alignments, Fragile Paint, Weak Acceleration, Poor Rear Visibilily Due To B pillars, Wet Weather Traction, High Speed Stability at 130 mph +, Insurance Costs.
996 TT
Pros: Unbelievable Acceleration...its as fast from 60-120 mph as it is from 0-60 mph, Amazing Grip, Unbeliveable Braking, Ride Quality, Chassis Stiffness, Tire Wear, All Round Visibility, Paint, High Speed Stability, More Interior Room, More Gadgets like Nav etc.
Cons: Price, Build Quality..a few weird gaps in the dash, Cheap Interior Materials, High Oil Consumption, Stiff Shifter, Slight Turbo Lag, Gas Mileage is 11-12mph, Really Awful Dealers, Looks Like A Boxster On Steroids.
I track the 996 TT, it's faster than most fully prepped fast cars.....
Friends often ask me which I like better and I answer them this way. The NSX is a foil (fencing) and the 996 TT is a sledgehammer. I liked them both A LOT, however ultimately I prefer the 996 TT. However you will be happy with either, that I can promise you. I would pick the NSX over a regular 996.
One last thing, my NSX T got a LOT more looks than my 996 TT does....if that's important to you.
Here's a link with pictures of both.
http://www.nsxprime.com/ubb/Forum16/HTML/000379.html
[This message has been edited by kinnsella (edited 10 January 2003).]