Not a hugely long ride - but enough to get a good impression, I test-rode an F800S, and here's what I thought: F800S is a VERY nice bike to ride - I enjoyed it a lot, with certain reservations.
It handles very well indeed and is far pokier than it sounds - open the throttle in any gear at any revs and it leaps forwards very nicely.
The bad points though were the ABS, which AGAIN cut in on me while I was braking hard on a bumpy section of road (when I did NOT want it to - scared me silly when it did. ), the fork dive (which I am just not used to anymore), and other very small points which weren't enough to take the shine off, but would definitely be fixed if I were to buy one (eg the nodule on the side-stand which you used to flick it out is not accessible enough - it needs to be just 1/2 an inch longer so you can get a boot to it easily).
The clocks were reasonably clear - but the tiny numbers didn't help, and the engine sounds like a hairdryer on it's last legs.
The belt drive was good - didn't make any difference to the way the bike felt and seemed to work well. Gears seem well chosen, and I was at home on the bike instantly.
It has inherited the indicator switches from the big bikes, and the switchgear/levers/light cluster appears to all have been carried over from the new, big K's. Both the F800S and R1200S use the light cluster from the K1200R/R1200GS which I suppose makes sense from a manufacturing point of view.
There was an R1200S out with us too - which apparantly is very good - the rider demoing it was impressed enough to ask for a quote.