I have a current R1250RS and have found it to be a wonderful sport tourer. If you are happy with the bikini fairing on the R90S, the smallish screen on the RS will be familiar. The modern brakes and powerful motor make a current bike easy to like, and it handles really well. Also, the modern saddlebags don’t come open on their own. I routinely get 50mpg on the RS, while my R90S can drop under 40mpg if I’m having a bit of fun. I have a 29” inseam, and yet I can flatfoot the RS.
On the downside, all of the 1250s are heavier than the R90S, and the RS is harder to get up on the centerstand.