I have a couple bikes with Ovaltech and a couple with Biopace. I can't feel any difference from my bikes with round chain rings. One exception was a bike that I built up from parts out of the infamous Box O' Crap. I had a single 39 tooth ring Biopace that I put on a crank with a 52 tooth round outer ring. I don't know if it was one of the older versions. I could definitely feel the pulsing as I pedaled, to the point that it was annoying. I took the Biopace ring off and replaced it with a round ring.