Depends both on what else is on offer in your area (sweet FA in my part of London, NHS classes only available if booked at conception/exceptionally vulnerable parents), and the local teacher, plus the makeup of the class.
If you have someone in the class who wants to be drugged as much as possible for the whole thing no matter what, and someone else who is totally wanting the most hippyish natural experience again no matter what, and the others have heard there can be problems in intervening too much but are all a bit scared in general, then any teacher is going to have a nightmare trying to please everyone.
Luckily my class had both a great teacher (who also did the NHS class, trying to get 16 hours of material into 4...), and we were all the last category, similar ages, etc, and we got 4 hours on pain relief because we wanted it. We happen to have stayed in touch a bit but that was a minor benefit.
So for me it was the most useful thing I spent money on - yes it was also the most expensive but it gave me info on what I didn't need to buy and where to get bargains.