I think it is good to attend if you can, especially with your spouse. It will be helpful and also gives you some mental preparation on what you can expect during delivery and when you go home. Also breastfeeding basics and physio sessions.
Even if you cannot absorb so much, it will also give your spouse the opportunity to learn more about the whole process. Plus you get to enjoy "massage" from your spouse as well.
I went to the one at Mt Alvernia, and the sessions seem adequate. The nurses & physios are nice and pretty good. I have heard rave reviews about the one at Thomson Medical Center with Mdm Wong Boh Boi, but I think that is very popular.