Its all about the money... like others are saying. Of course the GTR would be the advantage, and I've never really seen a GTS-T do as well as a GTR.
Personally I just recently bought an R32 GTS-T with a view for setting it up with a new engine and setup for track and other fun. I could have maybe just afforded a GTR but what is the point if you can't spend much money, afraid of thrashing the pants off it, or hitting something? Kind of takes the fun out of it, when you can't do what you want to do. I suffered that frustration with my R33 gts-t, and hence why I sold it. I wouldn't be making that same mistake again on say an GTR unless I had too much money to throw around.
I just see it as getting a stock gts-t to do "x", compared to getting a stock gtr to do "x" is just as much as a challenge, and just as much fun, unless you really must have the fastest car out there...
If it is then the choice would be clearly GTR and spend a hell of dollars on it.
Then I'd argue why have the R33 GTR for the street? if its all about prestige, just go and buy a BMW or something and use the GTR for what they're for