All these bikes have their day. The mystique that has built up around the R90S may well be justified although I know of a couple that are tucked away in sheds awaiting the day that their owner’s consider it worth digging them out to make a killing - not arrived yet. My first BMW and new bike was a R100CS in 1980 only owned for a short while as I was working abroad at the time and whilst away managed to convince myself that a Guzzi LeMans was what I needed. Anyway the R100CS was a great bike; I’ve had quite a few airheads since and might be rose tinted specs but I think the CS was probably the best.