Agreed. My Al bike isn't great, but I've ridden an aluminum bike that felt much better than the single carbon bike I've tried. I've never ridden steel (no one has my size!), but they're supposed to be relatively comfortably (Jamis, Surly).

Also, +1 on the fit. I think the carbon bike was a size too big (also a unisex bike so somewhat overbuilt for my weight), and now that my Giant is more properly fitted, it feels loads better.