Interesting, we swear by it. But I would say it really depends on your flight habits. As we fly mostly to Asia and Orlando, we get a lot of use out of it. The Capital One lounge in Dallas is amazing, we also use the PP benefit in Tokyo, HNL, and SFO when we pass through. You can also use Plaza Premium lounges, but they aren't in those airports either. Unfortunately I have found if you are flying United (term C in EWR or much of ORD) its near impossible to get anything but a United Lounge, which often really sucks for mostly anyone. They monopolize all the space, so the only card that would work is the United Club Card.
I would say that the lounge access alone this year has saved me about $300 in airport food or more, but once again I am the exception for a lot of people as I was on about 8 different intercontinental legs this year with a family of 6.