I'm afraid to say that although the s2 is stiff as a stiff thing and very fast, it is one of the most uncomfortable bikes I have ever ridden. The cabling made me weep too.
R5 is a million miles away, absolutely beautiful. Smooth, light, handles well, descends by itself, and stiff too.
Boss mode.
Seriously, that bike was amazing. As light as my r5 and like a sofa. Only problem was the HT was a bit long/slack