I ride a 63cm Litespeed Ultimate which has a very stiff front triangle and a more compliant rear triangle. I'm not as flexible as I used to be and 2 or 3 hours on this bike puts a beating on my legs.
Last year I had Litespeed build me a custom Pisgah for off road touring. What a ride! The rear end is very cushy while the very large chain stays soak up the vibrations. The first month I had it I put in 2400 km on single track and fire lanes.