Friends in the restaurant biz and friends who read that huge "Wine Spectator" magazine say the screw-top is actually better for the wine--a fully air-tight seal without the possibilty of the cork going bad which affects the taste of the wine (there's a technical term for this -- cork skunking?)

It does take some of the ceremony away from wine opening, but since you can't put a corkscrew in your carry-on, we make do.......