i installed it, played with it for 2 months, then un-installed, it works fine, i needed the camera to be dumb for me for a while so thats why i un-installed it.
no problems not even freezing, just don't go too mad with the settings.
I use it on my T2i. No problems so far and I have been using it for a couple months now. The ML software actually goes on the card and not into the camera so no worries on effecting the original canon operating system. FYI make sure you buy a fast Class 10 card to maximize the software's potential.