Yes, I am a member. The studio in Bonn is very nice. From my understanding, it has been open for less than two years.
They are a well-equipped gym, with 3 floors.
Floor 1= Weight machines, section with mats
Floor 2= Cardio floor (treadmills, ellipticals, rowing machines) about 40 in total
Floor 3= Free-weight section (99.9% guys) and another cardio section (bikes and step machines).
All in all, for the price you pay, it is a very good gym.
Cons:
-Depending on what time you go, it can be very busy. Between 4pm-8pm, it tends to be packed.
-No water fountains... (this may not bother some people, but i've never been to a gym before that didnt have a water fountain... I hate having to carry a bottle of water everywhere with me,

I would say join.