I find it can be very variable. Regarding evening drinks - Some lounges have terrible wine options (Ho Chi Minh - worst was an aussie Oxford Landing Sauvignon which is the cheapest of the cheap and the bubbly option was just an average prosecco) and some have great options (Singapore Robertson Quay - 2 types of champagne etc). It strikes me that the min standard is breakfast and evening drinks/canapes. Some do a high tea style afternoon tea which is a nice touch in my opinion. I noticed in Sydney for our last stay they actually had some free lunch items in the lounge which surprised me (pleasantly)