My experience is similar to Ray's. I prefer NomaCorc to anything else
at this point. Most of my wine is gone in 5 years as others mentioned
previously but I have 9 year old Mead's under real cork right now. If
the Nomacorc holds up for 5 years I will be satisfied. So far I know I
have some under Nomacorc for at least 2 years; I have to look later to
see if any are older. Keep in mind when they talk about screw caps
the usually mean a Stelvin which is rolled on by a machine...

Joe