Just saw this, and I'll add my two cents. Wine is a hobby of mine. Not just drinking to drink, but finding the good stuff at reasonable prices. Gambling supplements my wine habit. When I win, the profits go to wine. Therefore...
Screw caps are not bad. The reason some wineries are going to screw caps is because the cork supply is dwindling and the quality is getting poor. It used to be 1 bottle out of a case had a chance to be "corked" or become vinegar because of interaction with oxygen. Now it's more like 2 bottles in a case. Bad cork allows air to enter the bottle, which turns the wine bad.
Screw caps don't have quality issues, therefore oxygen doesn't mix with the wine. The same is true with plastic corks.
There is, however, an advantage to real cork. A miniscule amount of air allows a wine to age. Red wines meant to age still need real cork to reach optimal drinking status. That's why you see screw caps and plastic corks on mainly white wines and cheap reds.
So if you're looking for an everyday drinking wine that you plan on drinking in the next year, maybe even two, don't be afraid of a screw cap or a plastic cork. It doesn't change the quality of the liquid inside. But if you're looking for expensive win to set down for 5-10 years, it better have a real cork in it. Otherwise you'll open that wine in 2016 and it will still taste as if it were bottled last month.