Extremely satisfied.
Part of the reason I'm so happy with it is the cost. Its low, only $5 a month, and it means I have full access to all of the magic items in the Adventurer's Vault (MSRP $29.95), the character material from the Forgotten Realms Player's Guide (MSRP $29.95), and Martial Power (MSRP $29.95).
So by my lights I've spent $60 and I've gotten $90 worth of value so far, not counting the magazines or character builder. By the end of the subscription year, several more books will be released, and the value will continue to rise.