This is NOT a bashing thread. I would give comparisons on any two bikes I have the opportunity to ride. It just happens that I road a 2008 RK for about 80 miles this afternoon.
Differences I noticed:
The RK seems to have a little more "grunt" than my Nomad, and that's with the Thunder Air kit, TFI, and Roadhouse Dooley exhaust on my Nomad. It wasn't a lot more, but some. (EDIT - after switching back and forth between the bikes and really trying some throttle on the RK I need to change this observation. The RK has noticeably more pull than my Nomad.)
My Nomad is much smoother at idle but the two bikes are both very smooth when rolling. The RK shakes pretty badly at idle. The first time I backed off the throttle and started braking I thought the brakes were bad and shaking the bike. It was just the engine.
Both bikes have good brakes. I didn't notice any real difference between the two except that the RK rear brake squealed sometimes when stopping.
The transmission on the RK is much noisier than my Nomad's transmission. I do run Amsoil, but I have a hard time believing that with dino oil my transmission could make noise like the RK.
The 6th gear on the RK was nice. I'd like that on the Nomad too.
The stock seat on the RK is better by far than the stock seat on the Nomad. It was pretty close to the Mustang seat I now have on the Nomad.
The cruise control on the RK worked perfectly. I would really like to have that on the Nomad.
Both bikes have self cancelling turn signals. The RK has the signal switches on both sides of the bike, left for left and right for right. That took a little getting used to before I stopped trying to signal right turns with the left indicator.
The sitting position and bar position on the RK is less comfortable for me. I am 6'1" and I felt a little more compressed. I also felt like I was reaching for the bars more on the RK. I can't remember if my bike, when stock, was the same but I don't think so. I have the small riser extenders on the Nomad now.
The RK has just a little more "fall off straight" affect when being ridden slowly. It wants to fall to the side more than the Nomad.
The smaller and more curved windshield on the RK seemed to cause less turbulence. Even though the bike does not have lower shields on the forks there was very little buffeting. I had more air hitting my helmet but it was more laminar.
The temp was mid 80s for the ride and I did notice a little more heat on my right leg than with the Nomad but it wasn't anything to complain about.
The stock suspension on the RK was a little softer than what I am used to on the Nomad. It tamed the road bumps very nicely. I think I will back off on my Nomad's adjustable shocks a little to soften the ride.
The RK would pop on deceleration. Even with the mods I mentioned above the Nomad has no popping.
Well, that's what I can remember. It was interesting to ride a different bike. I thought I should share my notes in case anyone was ever wondering about those two bikes. I'll write-up whatever I get to ride next.