EOSHD has two good reads about David Cole of 3D rig builders Beampath testing the RED Scarlet and Panasonic GH2 side by side. His conclusion seems to be that if you don’t really need 4K or the post grading benefits of shooting raw, the GH2 holds up very well.

RED Scarlet vs Panasonic GH2
GH2 split screen vs RED Scarlet