This came up on a thread in the commuting forum too. I've got a 42t biopace chainring that I'd like to try out... but how do I tell if it's 1st generation? Where would you suggest digging SSS? I've done the biopace search for this forum to come up with a quote for the commuters, but didn't turn up anything more useful than: yes, it sometimes works well, and Sheldon does reccomend them.

or, I suppose I could just try it and see that way. Time to tinker!