I think it definitely depends on the group of woman that are in the mother's group as to whether you find it a good or bad experience.

I am lucky that my mother's group from my son is a great bunch of supportive woman and we all get along really well. It's been 2 years now and we still catch up weekly at each others houses.

I've heard disaster stories about some groups though. The most common gripe I hear is about overly competitive mothers. "MY child can do this! Yours can't" etc... We all know kids develop at different rates so I see no reason to be competitive. There's a huge difference between being proud of your child's achievements, and bragging in a way that puts down the other children.

In my area you only ever join a mother's group for first babies, so DS has a lovely bunch of little friends to play with and grow up with. I feel bad for my DD because she has no mother's group buddies, so a much smaller number of little friends Luckily one of the Mum's from my son's mother's group had a baby a month after my DD was born, and another is pregnant. I already feel guilty that DD's 1st birthday party is probably going to be a much smaller affair. Especially considering I didn't form a bond with her BB belly buddies like I did with DS's, so no BB buddies for her either, whereas with my DS we are all quite close and catch up in real life regularly.