Our first priority is always to produce the highest quality wine we can. The most frustrating production issue we face is when we do everything right in the cellar, but the finished product has this skunky, mildewy aroma when the cork is pulled.
Screwcaps in place of corks solves this very real problem with TCA (a molecule that is created in 5-8% of corks by the interaction of bacteria and chlorine used in their processing), but history is still short when we think about using screwcaps for those wines that are meant to age.
We are at an interesting juncture in the history and stylistic preferences of American winedrinkers. Most wine purchased in America is drunk almost immediately. Producers recognize this and have been making wine that emphasizes fruit-forwardness and softer tannins. Whether the style came before the purchase, or the other way around, the growing popularity of a closure that helps to reinforce the fruit and structure prevalent in many of today's wines has made it a truly viable alternative to corks.
The chief advantage of cork is its ability to let air pass through into the wine and from the bottle outward. The wine's dance with oxygen is one of the many chemical reactions that occur in wine, and it is very important in the wine's long-term maturation. One can modify the plastic liner that sits between the metal and glass of the bottle to allow more air in but the effects are not those, yet, of cork. So, for those wines (such as our bigger Cabernets) that benefit by slow aging, we'll stick use the humble bark plug.
For more on screwcaps, take a look at this video.