When you go to groups in iOS 5, you simply touch a group to open it. In iOS 6, you touch the group and a checkmark appears; then you touch done at the top. While this allows you to open more than 1 group at a time, it adds an extra step to opening a group. i do not like it so far.
I am used to it now; but I do not like the extra step. I never need to combine groups. I come from years in the Palm world where contacts worked much better and still do on my wife's prehistoric Centro.
