I can agree to almost all of the above and routem in particular. Although I now have PP through AmEx Platinum, I used to buy the annual sub for myself as I was doing so much travel as a freelance consultant - but the clients would not usually pay for Biz! That's how good I think it is.
The 'Just-Turn-Up' aspect is vital, particularly if you get a sudden cancellation/delay. The PP website is very good and you can download details to a PDA. If I am visiting an airport I do not know, I usually just print out the location details in my itinerary. Bangkokeasy is correct that you might want to search and some places will have quiet corners however, my guess is that, if you can afford a trip of this nature - then you can afford some lounge passes of this nature!
It is true that food/service/facilities are variable because PP is an umbrella company that provides access to lounges all around the world. Otherwise, you have to research each airport web site individually and find out what kind of lounge it has and where it is. PP does all that for you.
For example, a number of the UK Servisair ones don't offer more than pre-packaged buscuits, cake and bags of crisps (but there is some fruit), whereas the ones in South Africa are brilliant and the sandwiches are the best going with a never ending supply. In particular, in the mornings there is a loaf of sliced bread and a toaster!!! You get to make it to the setting you want.
On my last trip there, we had a four hour layover in JNB and, after checking in for the domestic sector, we had a shower and food and internet and snoozed in the arm chairs. Worth every cotton picking penny.