Ok, throwing my 2 cents in here!!!
I have a 2000 SV650N. Yup the naked..
I do a lot of 2 up riding with my daughter when I have custody of her. During the summer, I usually ride alone.
I'm 6ft 1in. and am not aging gracefully for my 45 years. lol
I have had the bike for about 4 yrs now. Have done several weekend runs from central PA to NJ for race weekends (I was on a pitcrew for an SCCA team).
Along with other trips to DE, MD, VA, WV.
The only mods I have done to the bike are a $10 Crampbuster, K&N air filter.
For the seat, I was recommended to get a set of the bicycle shorts with the gel pads in them. (Again, Thanks Garry!!!) Made a world of difference as to how long I could be on the bike.
On long rides, I will sometimes stand up, just to stretch. Especially on the long boring highway stints.
As for keeping up, my daughter and I did just fine this past spring keeping up with a bunch of Conny's. Of course we were WOT more than they were.
But we managed to keep up just fine.
And as far as comparing the Ninja 250 to the newer Ninja 650, or Versy, well they are totally different bikes..