Just installed mine and as Robert Kelly mentioned, it didn't seem like a significant change, but you can feel it. Full open throttle with the old one is painful on my wrist, whereas the R1 tube was only uncomfortable. In a way I'm glad it wasn't a huge change otherwise it would be downright dangerous. It was a trickier install than I expected, so here's a few tips: 1) Remove the brake control, it'll make the throttle change much easier; 2) tape that plastic washer to the grip when installing; 3) My throttle cables didn't have much slack (even with adjusters fully in) so I did resort to pliers to mount the return cable.
-pr