Depends on how it was shot.... I'd say the EX could probably get better images, but I loath the xdcam format in general.... I've seen stuff shot with the Sony 700 camera in 50 mb/s that my 7d would kill as far as image quality.
Get some good lenses for the 5dmkii and I would say you'd be stacking up pretty close. The EX might be a little sharper image.