I don't have a 1D C and am unlikely to own one anytime soon-- but "stability issues"? Given that Canon reps were at one point saying the 5D Mark III hardware couldn't support uncompressed HDMI-out (a demonstrable falsehood at this point), I'm somewhat inclined to be skeptical. And even if the issues are legitimate, I'm sort of astonished that Canon has been so silent about the firmware updates, especially after Black Magic stole all the NAB thunder, and after Sony showed off 4K prototypes aimed squarely at the C line.
I know there's an argument that says Canon knows exactly who its customers are, particularly for a low-volume product such as the 1D C. Maybe high frame rates don't matter to the target audience. The C100 and C300 are certainly built around that philosophy-- that is, they might lose out in absolute image quality to Black Magic, and they might lose out on specs to Sony, but they compensate with ergonomic advantages, workflow simplicity and other variables that working professionals care about.
But man, if Canon's assumptions about its customers are askew, the company could find itself playing from behind in more ways then spec sheets. Canon's sales say that the company is doing fine, but it all reminds me a little bit of Microsoft. Microsoft missed the boat on mobile smart devices and consumerizaton trends, and now it faces a future in which Android will own more devices than any other OS, and in which Apple OSes will have about the same overall market share as Windows. That's the analyst expectation for 2017, anyway, and if they're right, it'll be a big adjustment for a company accustomed to de facto monopolies. Microsoft has a lot of ecosystem advantages that have been mitigated by outside forces. I have no concrete basis for suggesting Canon is similarly vulnerable, but I think there are some parallels.
Blergh... okay, ending rant about products I neither own nor am likely to own.