You need to check the lounge coverage yourself using the web sites. The reason I say this is because the lounges included actually vary depending on what country your membership is in.

Many of the other readers on the thread may not be aware of this. American PP memberships typically do not include many airline lounges, only third party contract lounges. However European PP memberships include all UA lounges including the LHR T2 lounge which is excellent. That alone makes it considerably better value.

Also, you should have realistic expectations. If you've seen photos of LHR and JFK premium lounges and expect that in every US airport you'll be disappointed. Most US lounges have power and comfy chairs and not much else to distinguish them from the rest of the airport. Food is often just crackers and cheese and they usually don't have showers (or free drinks if that's your thing).

IMHO the only time when lounges are really worth shelling out significant amounts of money for are connections at a major hub after an overnight flight. Ie, in London on a JFK-LHR-xxx flight you get a shower and light meal and show up looking mostly human instead of a disheveled half-asleep zombie.

The rest of the time they're a nice-to-have but not really worth paying for. And I've been in airports when the rest of the terminal was frankly nicer.