Andrew Reid the filmmaker and video editor that runs the EOSHD camera/video blog has made a very good test comparing most of the current mirrorless and DSLR cameras that shoot high frame rates at 120fps. This is not only a hard test to do because you need all of the gear but you also have to analyze the results based on per pixel quality, detail retention, dynamic range, and color information.
The test footage is easy to follow and will really help you in deciding which camera is better in slow motion. The results help level the playing field between these cameras and lets you compare the performance vs price. We wish the test included the new Sony a9 Mirrorless camera which we know delivers superb image quality at 120fps.