I make use of a Priority Pass provided by American Express. I don't really use it anything like enough to call it good value for money but it is a convenience I enjoy having and intend to keep.

Priority Pass is good if you use it regularly and dependant upon the lounges you use. You should be aware that some lounges (particularly in Europe) will let you in for a charge of approx £15.00 in which case Priority Pass may not be good value for money unless you use it an awful lot. I understand that US club lounges can be a lot more expensive than this though.

You also need to be aware that while Priorty Pass covers a lot of airports, it can occasionally be quite useless depending on the airline you're flying with, terminal you're departing from and so on. For example, if I get a BA flight out of MAN or a KLM flight from AMS to MAN, the Priority Pass is quite a useless piece of plastic.