As sharp yes and no.
Factory blades like Feather, Persona, Derby etc. single or DE are
commonly enhanced with a thin layer of teflon that
does change the feel of a shave. In fact a well honed and
stropped str8 can be sharper than a coated blade but not "feel"
as sharp at the time you are shaving. Later in the same day
and tomorrow is a different thing.... YMMV.
Check out US patent 3071856
http://news.google.com/patents/downl...erview_r&cad=0
The patent is interesting both from the perspective of the
date and from the discussion of temperature control needed
to keep the temper intact at the same time fuse/ cure
the teflon. The tight temperature control requirements to
keep the temper may be why some DE blades only give a couple
good shaves while others give many more.... or the brand is
very spotty in terms of quality.
Other tricks are also used but a correctly freshly stropped well honed
str8 is about as sharp as any razor can be. And a str8 can ultimately
be tuned to the preference of the shaver by the shaver.