Never as much as I'd like to - like all my bikes once the short days start setting in. My weekends just disappear at the moment.....
It's the bike I've been riding most though - since I fitted the RC39s - but the FSR has had a couple of outings and last time I was on the F6, which has also improved its ride with the RC36 Evo III compared to before with the RC38.
To be honest there's not much between them at the moment - they both weigh the same as the UST tyres cancel out the frame weight savings and the Ti seatpost gives similar shock absorbency to the carbon seat-tube. The wider, more grippy tyres and shorter stem on the RC300 make it that bit more predictable, whereas the F6 feels a tad livelier.