First give your insurance company a call and see if there is difference between the two. The biggest reason I bought the rr over the 636 is I got a slighter better deal (a few hundred cheaper) and my insurance was 800$ less a year!
The 636 will have a stronger midrange than the rr model. The rr has slightly higher compression with forged pistons to make up for some (not all!) of the power output of the 636. The rr also has an adjustable swingarm that you will likely never use, and a slipper clutch that you may

. As far as comfort goes the bikes are identical, but off of the dealer floor the rr will come with stiffer settings.
If for you both bikes are the same insurance cost, price, and you don't plan on heading to the track with it, I'd go for the 636.