I must say I'm not impressed.
There is a bland uniformity to the site, and it seems that the entire group is dedicated to chat and discussion - not necessarily sharing information or being a repository of such. My MSN groups were more than just discussions and messageboards - they were/are a place to go and have questions answered, to find both information and pictures, to post creative ideas in an eyepleasing format.
They are unique, and easily identifiable. When you visit, you know what they're all about. Not so much Windows Live Groups.
Just for comparison: screencaps of
IR Central at MSN Groups and
Tracy Island at Windows Live Groups. Which one is more distinctive? Which one is more appealing? Which one promises more dedicated information? You tell me.