I've found many DL, NW and CO lounges are part of PP, but not many UA (at least at ORD

). I wish it were nearer to the UA gates - or at least in the same terminal as most UA flights!
If it works out for you, I agree that $625 is high to spend, if many of the same (or near) clubs can be had for less.
If you want to know about specific PP locations in the airports you travel to most, PM me and I can help!