I always used feathers with my DE but now I only straight razor.
I would say a straight can defiantly be as sharp as a Feather blade.
My shave s with straight are as close or closer than with a feather , although ive never tried a shavette .
I also thought that the point of Jnats and Eschers was to achieve the ultimate sharpness but have it feel like it wasn't sharp?
I could be wrong