I went to ours, there were only three though, one where they did stages of birth, which was quite physiological, the second one was pain relief and managing your pain (i.e. pre pain relief, e.g. ways to distract yourself an handle contractions in early labour), and the third one was interventions and the hospital tour.
As other have said you can do the hospital tour yourself (I found this useful and you can see e.g. which rooms have birthing pools in, if that's something you want, and you know what to ask for), the interventions one was a bit meh because TBH if you need one of those, it's not really going to help knowing what e.g. a ventouse looks like.
The one about stages of labour you can read on the internet or in a book, and pain relief, again you can do some reading, and ask questions here. I found asking here was way more useful than asking in class, because you get 50 people's experiences and opinions rather than just what one midwife thinks.
So go to them if you can and want to, but if you can't, don't worry, you can do the planning and prep yourself.
D