I got mine about noon last Friday and had 570 miles on it by Sunday night -- I'd say it's pretty comfortable for riding long periods of time. Make sure it's fit for you though. Many of the dealerships have parts of the U-fit system but not all the parts needed to have the "fitting dummy" set up. I thought stock foot position (#3) was comfortable when I sat on my F3-S in the store and parking lot, but within 10 miles, my left knee started yelling at me. I was going to go back and get the position 4 linkage (1 notch longer) that same day but a series of accidents that happened between us and our route back to the dealership caused us to have to change our route enough that it was easier to head home on Friday and just go back on Saturday morning. The new position made it SO much more comfortable, I could ride all day every day.
We spent most of Sunday riding 2 up, and the passenger seat is much less comfortable than the RT (the backrest is on backorder, so I'm unsure whether having one would add to the comfort or not). If you ride mostly 1-up like I do, I don't see any reason to not get it and use it for long distances. I will be.