Interestingly I had my old 1st generation Tikit and a newer 2010 Tikit for a season. When I was deciding which one to keep I was aware the newer Tikit was noticeably stiffer than my older Tikit. I eventually kept the older Tikit because in practice the extra frame flex had zero impact on my actually riding experience and I'm one of those idiots who has to race from light to light on a folder. I certainly didn't feel keeping the older bike was a downgrade.

My latest road bike was custom built for me with the lightest guage skinny tubing practical and it's a rocket ship - especially uphill.

I think the whole pursuit of an ultra stiff frame is misguided and doesn't result in better performance in the real world for normal human cyclists.