I've had a Priority Pass for two years now and like it quite a bit. I've used it primarily for international travel (as I've been living in Europe for the last three years) and occasionally in the U.S. I like the flexibility and the fact that I usually have multiple lounges to choose from in each airport.

On the down side, you have to pay for each guest ($27.00) and the lounges that PP contracts with may not always be convenient to the airline on which you are flying (different terminals, etc.)

Overall, though, I'd recommend it.