Praxis Bottom Bracket Performance on BB30 Frame
I installed that Praxis BB30 converter on my Cannondale and I will never look back. I switched to a Shimano hollowtech II crank because that's the one I had lying around.

Not only does it feel more rigid, but the bb30 was hopelessly noisy no matter how often I cleaned it, and the Praxis BB has been silent so far, the bearings seem to seal better. So yes, it's rigid, quieter, easier to clean, and my frame doesn't seem to mind. Those are my findings.

Just make sure you use the proper amount of anti-seize when installing.