...........really depends. For the Connections member price of $11.25 they definitely are. For $15 to $20 on ebay, plus any appicable shipping, you can only use them at a couple of places to get your moneys worth.
The Q&C vouchers are good at most WDW counter service locations. They cover an entree (ie - burger, etc.), side (ie - fries, etc.), dessert, and drink. At most counter service locations that won't cost much more than $12 - $15. That being said, the Q&C vouchers are good at Beaches and Cream (at BC) and Pepper Market (at CSR) where you can easily order $25 worth of food that is covered by a single voucher.
All I can say is that I hope those who get them on ebay use them at the right places, otherwise they are getting ripped.