I own an Alexa Plus and I heard Canon call this a Red and Alexa killer. It's nice, but not true. With the C300's 8-bit 4:2:2 MPEG II codec, Canon has committed professional cinematography suicide, unable to kill anything, let alone the holy trinity's (Sony, Arri, and Red) 12-bit 4:4:4 codec(s) that makes DI color correction possible. No major production is going to risk their money, and images on the thin negiative 8-bit leaves digitally embedded on its CF cards. Sure the camera has an HD-SDI output, but what about Steadicam? I guess you'll just have to spend another $7K for a 4:4:4 recorder.
Another non-starter is that Canon, dispite having an amazing lineup of EF lenses, didn't include a way to servo control the focus of its lenses. I own every Canon EF L lens from the 14mm 2.8 to 400mm 2.8 EF IS L and pray for the day I can run them on my Alexa. Sure I have Master Primes, but there's nothing like Canon's 400mm.
Don't get me wrong, while I applaud Canon's vision, it's pretty miopic not to go just a little farther, and give its customers, and potential cinematographers what they truley need to go head to head with the big dogs, UNLESS, it's their way to sell 10 million units and then in 12 months announce the C300P, the "professional" version that incorporates servo control and a professional cinema codec as a way to double sales. Don't believe me? Just read a shampoo bottle's instructions written by a marketing guru: "Shampoo..REPEAT and rinse." Can't wait to see what Nikon has up there sleeves. Maybe they'll adress these essential issues.
One last thing, the camera, whether it's an Alexa, Epic, or C300 always takes a back seat to script, direction, acting, lightning, cinematography, and editing. Try watching the latest retread movies, like "The Thing," that in all its 35mm splendor, sucks.