Aw jeez. I own a R3R too, but ****. No love for the R3T? The thread pointed out above is a good resource but here's the skinny:
R3R waaay different foot position: It's closer to a standard riding position and can sometimes get a little cramped, but it gives more room to lean.
Fatter rear tire: looks badass, makes slow speed maneuvers a bit more difficult, but really...it looks bad ass...but comes with fewer tire choices...seriously, bad ass though.
Stock HP is higher: Doesn't mean much, reflash the R3T and bam it's the same output. Annecdotal observation is that the R3T always puts out a little less after modification. In my head this is because of the angle of the final drive on the R3T is sharper than the R3R...I may be completely full of **** on that one though.
And....umm...R3T has more lights on the front...