About three months after I bought my Canon C200 video camera last summer, Canon released the C70. At the time, I rationalized that the trade-offs between the two models made it kind of a toss-up about which one was "better." With time and experience with the C200, and reading the observations of others and their experiences with the C70, I'm starting to feel like I should trade mine in.
If I'm going to do that, it might be urgent, for a few reasons. First, the C70 adopts the new RF lens mount, which is obviously the future when Canon is not likely to introduce new EF mount lenses. I imagine that they'll be available for a very long time, but their line of still cameras make it pretty clear where the future is. The C200 is also four years old, with no update, and if they do stop making it, I imagine its value will plummet. Even when I bought it, the price was a couple of grand less than when it was introduced.
The first thing that I rationalized was that because the C200 had raw recording, it didn't matter if the non-raw codec was recording 8-bit 4:2:0 (meaning it sees 16 million colors instead of a billion, and sub-samples the color resolution). As it turns out, raw isn't great because the file sizes are enormous, and an hour of video at 24 fps requires half a terrabyte of storage. I learned almost immediately how impractical that is. While you can transcode to a more manageable codec, that's another step and you still need to fit the original at least for a little while on your disks. Furthermore, the less color information seems to be the source of things getting ugly when I attempt to adjust for my sometimes poor exposure or color tweaking. This might be me and my weak skills, but I've seen color banding by the time I upload online, and a lot of softness around the edges of punchy colors.
The image quality is pretty great, provided I expose correctly. That's the case when I'm lighting a room, but I often get it wrong outdoors or daylight lit interiors (yeah, I'm talking cat videos). As others have described, the C200 is a little more forgiving if you over expose a stop or two, but not so much if you under expose. You get a lot of noise in the shadows, and I've seen plenty of that. Again, that's me not using the tool effectively, but many tests on the Internets show how much the C70 let's you get away with, well, inexperience. And yes, you can get away with it shooting raw, but as I said, that's often impractical.
There are some little things that add up, too. The C70 can do auto ISO, which I've learned from the R6 still camera (I need to do a review of that) is a surprisingly useful feature when you want to achieve a certain depth of field by way of aperture and sharpness by shutter speed. It's another creative option. It also runs longer on the same batteries, can do glorious 120 fps slow motion in 4K, all-I recording up to 30 fps, and the EF mount adapter is actually a speed booster, meaning you'll see nearly the entire frame of what your lens sees, focused on that super-35 sensor with more light and sharpness.
I'm trying to learn from buying into aging or unpopular technology, as I did with my old Panasonic AF100. The Micro Four-Thirds mount appears to have no future (glad I only bought two lenses for it). It feels like there's a shift happening.