Soggy floor boats can track really well, and aren't a big deal if you have a boat full of gear and a floor in the cockpit. Your boat will bail slower, and feel heavier in the rapids, but on the Colorado it's all about how you set up for the rapid anyway. It's just a matter of personal preference I guess.
When I came to the Poudre and had to raft flows of 50-100 CFS in August I learned quickly to partially deflate my whole raft to help it slide over and around rocks. I run a soggy boat at low water, for opposite reasons of the above comment, of course. I guess the point is, rock hard isn't always the answer for rafts.