I've got Biopace rings on both my Trek 820 and my Schwinn 354. I
hardly even notice the difference anymore. I switch around from one
bike to another so often I guess I just know how those two will feel
when I ride them. Now, if the BioPace were to disappear from those two
bikes...then I might notice.

On a simialar note, I think I notice a definite ride difference between my
steel frames and my aluminum frames. I usually like the stiff aluminum better
though sometimes I'll be in the mood for a recreational romp on a steel frame.
Isn't it strange, the things we notice about our bikes?

Happy trails