I used the Petzl grigri before, lost it, and bought the Cinch, because it is cheaper. I got used to it after some minutes of playing, and now, after two years of use, i won't touch a grigri again! It simply feeds so easy, is light and small, and feels very good in the hand. This is the climbing gear i am most satisfied with!
I haven't tried the new grigri 2, but it's basically just smaller and works with thinner rope than its former model.
Watch the technique video on youtube: http://www.youtube.com/watch?v=R9TO5ikqXwo