I am not positive but I am an AMD supporter. I know several people here at school with 1Ghz and I know some others too. From what I hear they are pretty stable and seem to run at blistering speeds. I would say if you are paying a lot more than the 1Ghz, go with the lower of the two. But if you can get it at a good price Go with the 1.2. I hope this helped you out a bit.
-=-Sean-=-