I've owned every 1 series digital canon produced, from the 1d ccd to the current 1dx.
Of the list the only Canon related issues were with the 1ds2 which would corrupt if you reviewed the lcd while the camera was processing images and Canon eventually addressed it, essentially by slowing down the lcd review.
Of the other issues, two shutters which CPS replaced in two days each, at a reasonable costs and I lost a sensor in Hong Kong that they replaced that day. The sensor issue was my fault and a long story.
Keep in mind our studio has over 400 terabytes of imagery stored, most from Canon cameras, so those three problems are minor for the amount of use and abuse we've put the 1d series cameras through.
My 1dx I bought for stills, but also for the ability to shoot high fps cut frame video. We've had multiple sessions where we've shot over 9,000 still frames in raw and jpeg and also for video in jpeg mode only and never had a problem, which I'm amazed because the abuse of shooting that many frames with a mechanical shutter and a moving mirror at around 15 fps must be tremendous.
If I do have an issue I'm sure CPS will fix it in days, usually two.
No camera is perfect and it can be frustrating to have the one with the issue, when others say they don't. I'm sure that the people with issues are frustrated, I'm sure the people without problems think . . . huh?
Once again out of the 1ds1,2,3, the 1dx, the 1d1,2,3,4 to have so few problems considering the volume and compressed schedules we work under I find more than good.
Canon takes a lot of heat, some people find them non inventive, but no camera system we own always travels the world with us, because no camera system I own is as versatile and robust, but I would suggest anyone that uses a Canon under heavy professional use to join cps. It's well worth it.
IMO
BC