Good or bad?? hmm... depends if money is not a problem and just want him to swim and not care how long does it take him to really know swimming.
Who takes your kid to swimming?
I see mostly are helpers waiting in the waiting room. Do they report to you how's the kid doing?
I took my kid to swimming every time, change 2 locations. Did complain once about the teacher teaching method. after 1 year, decide to stop. That time we thought my son really not good at this.
Few months ago, found a teacher in public swimming pool. around 3 months, he can swim without any support in the big pool. ratio only around 1 - 3 or 4 kids. sometimes, 1- 1 or 2.