I have been going to this gym for almost 2 years now. It does not require a binding 12 month membership which made the deal for me, I can just pay month by month.
The gym is very spacious, modern, and clean, located close to Mall of Scandinavia. There are a lot of machines, treadmills, bikes, and cross trainers so even in the busiest time you don't have to wait in front of the machines. In the evenings and weekends after regular classes you can start your own virtual training class in the group training room. Air-conditioning works great even in the summer heat.
For an extra fee one can rent clean towel, Adidas work-out clothes, and a personal locker (to store e.g. drink bottle and work-out shoes) which is very convenient -- you don't have to drag a heavy training bag with you. Personnel are always very friendly and helpful. They also sell coffee and some healthy snacks in the lobby.
Only thing I would add are Pilates classes -- they are advertised on the gym windows outside but have not been available in schema.