Let's get the big bullet point out of the way, these new DSLRs from Canon have 50.6 Megapixel sensors. That makes the 5DS and 5DS R the highest resolution full-frame DSLRs out there and happily unseats Nikon as the new king of the Megapixel throne.
With all that resolution, Canon made sure to back that sensor with their Dual DIGIC 6 image processor system, a 61-Point High Density Reticular AF array plus up to 41 cross-type AF points. They've also reinforced the camera chassis, baseplate, and tripod lug to increase image stabilization and they've even added new setting intervals to reduce any potential camera shake before you release the shutter.
The camera will be available in two models: the 5DS ($3,699) and the 5DS R ($3,899) which has no low-pass filter. The cameras are available this June. More info at canonusa.com.