I have been on both sites. If I want intellectual debate this is the site to visit. If you want to know about benefits or things happening locally such as children's activities etc. then the other parenting site is the place to go.
Also if you mention things like private schooling on the other site you might as well stand in the town centre and announce that you are a snob. There is also a lot of 'my husband is a doctor', 'my husband is blah blah blah' type of posts which leave me thinking 'what about your own achievements?' That said though, a lot of people there can be very supportive etc.
I don't even know why I'm posting this, boredom I guess?