I can only compare them to my favorite blade, the red Personna. They are sharper but to me not quite as smooth. In all a very good blade.
Len
Are you guys talking about Astra Keramik or Superior Platinum.
Yeah, Astras are by far my favorite blade. Much smoother than feathers, but comparable in sharpness (except ever so slightly less sharp). Also much sharper than Red Ps, but just as smooth.