Today I shot this comparison between the 5D Mark III and hacked Panasonic GH2 with EOSHD Unified Patch. The results are all in the video.
Now you just need to factor in overall aesthetics to your decision, which are important. Personally I’d say that full frame sensor aside there is no reason why I like the 5D Mark III’s cinematic image more than the GH2’s. But I do need a full frame camera! It is another look, another option.