According to the Gambero Rosso, something happened to Capannelle after its Chianti Classico peaked with the 2001 offering, which earned 2 red glasses (excellent). The Classico dropped to 1 glass (slightly above average) for the 2002 and according to Gambero Rosso, they did not make a 2003. Of course, 2002 was the worst vintage for over a decade in Tuscany, but that doesn't explain the lack of a comeback in 2003. Their collaboration with Avignonesi di Montepulciano, "50 & 50 Avignonesi e Capannelle" (Merlot & Sangiovese), is still consistantly highly rated each year with several 3 red glass (top prize winning) awards. They have a very interesting website, which is fun to explore.
Interesting reviews on CellarTracker: