My knowledge is date, but may still be valid.
When I was shopping for a used Boxster in 2004, I test drove the Boxster, BMW's Z3 and the Audi TT. I had very high hopes for the TT because I find its aesthetics appealing. However after no more than half a block driving it, I took it back to the dealership. It looks nice to me (the first variation, anyway, which is what I tested), but I felt like I was sitting in a bathtub. I hated it. It was like driving a Checker cab.
My '01 Boxster now has 130,000 miles on it and, although I had to replace the engine, which I was not happy about, it is solidly a driver's car.
I think if you want a driver's car -- regardless of whether you race or track -- the 718 may be for you. If you want something more luxurious or flashy (and that has its appeal, certainly), you're more likely to go with the increasingly upmarket Boxster or a 911.