I was in this lounge last night and it's very basic. No showers but there are restrooms with sink, mirror etc. They have a private smoking lounge for users of the lounge.
Two beers on offer a local on "St George" and Hieniken but be prepared to drink it from a plastic cup or from the bottle/can. Other soft drinks and such as juice and coke are available. I had a look at the food but unless you are starving to death its not worth the risk!
The lounge is a fair size with comfortable chairs and information screens, with three internet terminals by the entrance.
In regards to guests I think it just depends on what mood they are in. I met a fellow traveller who was in economy and asked if she would like to join me rather than sit in the waiting areas for four hours. I approached the desk and politely asked if she could join me and the receptionist said it was fine.
Hope this helps