i have one on my '05. i do find comfort using it on long runs, and i like the fact that i can quickly adjust the angle of the backrest.
for me, it was a bear to install!
the hole in the tang that is drilled for a support screw is way off, by i'd say a strong 3/16". i was able to use a small c-clamp to force the tang back far enough to drop the screw in. forget trying to thread a nut on the bottom of the bolt, no room. i also had to counter drill the hole a bit so the seat would lock in the latch.
you need to remove the existing screws as they are too short, the provided side mount screws need a pair of needle nose pliers to hold the nut as you thread the bolt in, no way to get a meaty finger in for the task, and i don't have meaty fingers.
these reasonns don't make it very convertible, meaning it takes about 10 mins to remove it. there's no way a passenger can sit behind you with the backrest installed and the top case mounted, unless they are very tiny. it is solo use only.
cadman