Economy gives 10 points per sector (20 points per visit!) 500 points for Silver, 25 returns. I don't know if the web fares qualify.
The lounge at LBA is .... compact, there is currently a sign on the door saying Gold members only (which is contradicted by the web site and by Diamond Club). The lounge staff (generally) guard entrance as though their lives depend on it, I saw Darius (Pop Idol) being refused entry, despite an official invitation.
MAN lounge is a bit bigger, and seemed nicer. More rotations from MAN, and possibly cheaper prices?
Hope this helps a bit.