Actually went from 997S to 996TTS (got a new 997S when I grew impatient waiting for my 996TTS to be built)....did about 7K mis in 4-5 mos.
IMO, 997S is easily world's best $100K car.
But not a fan of the 997's Beetle-like headlights; wimpy-looking rear wing w/the accordion-like feature when raised; and busy dash w/too many little buttons/cheap-looking aluminum touches and lame-looking steering wheel. Also, at least in US, still hard to fully spec 997S w/all the leather and deviated stitching one can spec on a 996TTS...net, net, like a well-spec'd 996TTS interior over a 997S interior w/just "full leather" trim...
Dynamically, biggest prob is nonlinear steering ratio of 997S (counterintuitive to anyone accustomed to F or 996TTS)....to me, "new" steering ratio was hugely annoying in curves...Sound of 997S is far more interesting than "silent assassin" 996TTS. And 996TTS' turbo lag is a trade-off vs NA 997S' more linear response. But once turbos launch, the 996TTS is a different animal....
If have a 996TT, would definitely get a 997TTS on launch, but a 997S as a stop-gap car while waiting is a reasonable option....