I beta-tested one of these in my town. Was quite a lot of fun, but our group solved it too fast (I think we finished after 30 minutes while the room was planned to take about 50 minutes to solve). They fixed this afterwards.
The fast-paced group problem solving is quite enjoyable, although I still think it's not worth the 20 € / person they usually ask.
I find one of the most fascinating questions about constructing an escape room is how exactly you calibrate the difficulty for different groups of people. Some people will finish the room in 30 minutes like you, but others will be totally stumped after 50 minutes despite it being the exact same room.
Both of the rooms I've done had a hints system so a staff member overseeing the game through cameras could send a hint any time we dropped significantly behind schedule.
One of them had a two-room system where you had to solve the first room to get to the second room, and in the second room I believe one or two of the locks had been unlocked ahead of time manually by a staff member, based on how quickly we solved the first room.
Of course every time anybody takes the challenge you acquire more data, and keeping an eye on the emerging patterns must be absolutely critical to engineer an enjoyable challenge for the maximum number of different people. Metrics!
The fast-paced group problem solving is quite enjoyable, although I still think it's not worth the 20 € / person they usually ask.