I couldn't decide either so I ended up with one of each, I have covered 7000 miles on my GS in the last 7 months and 1600 miles on the RT in the last 2 months.
We have decided that the GS suits us best because it's more fun. The RT is possibly the better bike, but on the grin factor the GS has it. My partner prefers to ride pillion on the GS, and for 3 reasons, the GS is more exciting, has more attitude and she can see over my head, where as she cannot see over my head on the RT and has to look around my shoulders to try and see up front.
However she prefers the heated seat of the RT.
The RT is a warmer bike, about 3 degrees warmer, so if you are comfortable on the GS at 6.0 degrees you will have the same comfort (warmth) on the RT at 3.0 degrees.
Handling? on long fast bends say 85mph onwards (where legal!) I think that the RT feels slightly more stable, but I think that this is probably down to the brilliant aerodynamics of the bike and not the suspension, plus it's heavier, it certainly handles very well indeed and is very quick through the twisties, however it is not going to leave the GS behind which I think is a bit more flickable though the tighter stuff.
We have been running our bikes back to back for the past couple of months deciding on what we liked best about each bike, it's been very close call, both of these bikes are totally brilliant and you will love which ever one you buy.
We have decided to keep the GS and are going to let the RT go, if I lived in OZ I would definitely have the GS to get more breeze, however if you are unfortunate enough to hit a Roo the RT will give you a bit more protection.
IMHO There isn't a 'better' bike, what it boils down to is what is the better bike for you and your pillion.
Give the RT a very long test ride, then jump straight onto your GS and see how it feels, it's a personal thing.
Good luck ride safe and please let us know how you get on.