I love OBEM. I was having our DD in there when they were filming the 1st series. I screamed my head off, so whenever there was an out-of-sight screamer, DH gleefully pointed out that it was probably me! 
This attitude that some people have, that labouring women shouldn't be noisy enough to make others uncomfortable, makes me very sad. If screaming helps, then scream!
As for the portrayal of the MWs, I think it might be a very skewed picture. I was in there for quite a while, (2 days of labour, and 5 days afterwards) so I recognise a lot of the staff. During the contractions I didn't want contact or reassurance, so people were just sat waiting quietly for me to stop. In between was a different story, they were very keen for me to get up and keep mobile, everything was explained well, and I was advised and coached. Everyone in there was fantastic, so helpful, professional and friendly, yet if you'd only seen me having a contraction, you would have never known.
Can't wait for the next episode! :)