The 550D was released almost exactly 2 years ago and it was a great leveller of the playing field, since it brought similar video quality to the 7D down to a more reasonable price point.
[vimeo]http://vimeo.com/44099284[/vimeo]
Because of the slow refresh rate on their high end DSLRs (the 7D and 5D line come out every 3 years) Canon seem to have been reluctant since 2 years ago to really upgrade the much more cheap and cheerful Rebel line for video. (Some may say Canon look reluctant to upgrade the higher end line as well considering how it took 2 years for the 7D to get a manual audio control firmware update and that the 5D Mark III has the same poor resolution as its predecessor!)
As a result the Rebel line is now dead for video and the 650D does nothing to change that.
There are several rival cameras which are better equipped at the same price point. The GH2 (with or without the hack) has the image quality advantage. Olympus with the OM-D E-M5 has the better stabiliser, faster AF and a punchier image (certainly consumers would be better off with that than the 650D, as would documentary run & gun filmmakers). The NEX 7 and NEX 5N has peaking and a APS-C sized sensor in a mirrorless body plus slow mo in 1080/60p. So there’s ZERO reason to shoot video on a Rebel.
Unlike the GH2, a NEX is probably a better option if you have a LOT of Canon EFS glass from a previous 550D or 600D. These can be used with the Metabones adapter with electronic aperture control, with a few exceptions. The GH2 can use Canon FD glass and plenty of other notable brands (Nikon, Leica M, Contax Zeiss), including an extensive range of video optimised lenses from Panasonic and Olympus. There’s also speciality glass like the Voigtlander Nokton 25mm F0.95 which overcomes the slightly smaller sensor and gives you an even shallower DOF and is 4 stops brighter than the brightest EFS lens (F2.8).
The 650D is also slightly worse for noise performance than the 7D.
So again – trust me there is zero reason to get the 650D for video and if someone has one please write to me! (Meanwhile the 5D Mark III at $3500 is on shaky ground as well because really the only reason for shooting video on that is because of the of the beautiful way a full frame sensor renders a good lens).