Its different skills for either bikes. The P20 brings the biggest smiles and the most satisfaction when its given some hammer and everything flows.
My Yeti 575, allows you to get away with more, yet also allows you to push further, faster and harder. It truly is brilliant.
The skills developed on the P20 enhance the skills on the 575, yet i can't thing of anything i've learnt on the 575 that makes the P20 better.
Its also difficult to guage skill against other bikes/riders. I've had the P20 chasing modern full suss round Glentress, but is the rider in front riding as hard? Having an off day? Lots of factors.
Bottom line? Take out the bike you fancy, the one that'll make you smile on that day