TY, all. from what's been said here, i'm guessing that i'm not a technical enough rider to tell the difference, but that there is a difference, even on non-GS road bikes.
back story:
when i bought my first BMW in 1984, they had a naked R100 and a naked K100 in the san francisco show room, which had just moved from duboce street to sixth street fwiw. i knew i lacked both the knowledge and the tools to understand or repair a fuel injected motorcycle, so i got the R, which was also cheaper. in 2017 i finally decided to try the more modern version, by which mean the 1985 K100RS, and of course i loved it, and so regretted not giving it a chance sooner. thus, when offered a drive on an R1200 i jumped at the chance, and hated every minute of what they call "telelever". thus, when i saw the "paralever" i didn't know whether it would be good complexity (like fuel injection and water cooling) or bad complexity (like moving all the front end pivot points around in ways that drove me crazier). adding a second U-joint to the driveshaft seemed especially fishy (moving parts).
verdict:
i'll try to become a good enough twisty-road rider that i'll be able to tell the difference between monolever and paralever, and then give it a chance.