I don't know if a DE blade is sharper than a straight but my Muhle R41 with a feather blade will give the shave I get from a straight a run for the money with a photo finish. The shave is not quite as comfortable though. If you have not shaved with a DE before try that combination for a does of lethal to your face.
I get about 4-5 shaves out of a feather blade.
Bob
I should add I do not mean lethal in a nice way. The R41 with a feather blade is not for a beginner DE shaver.
Bob