I've been using the new Canon 5Dsr for a few days now. I'm quite certain it'll replace my 6D, but I want more time with it to be sure.
- 50 megapixels; 8,688 x 5,792 resolution. Great for landscape shots and stuff you want to print big or view in really high res.
- Mirror lock-out support to minimize/eliminate camera shake. This is awesome for landscape shots.
- Better bracketing support.
- Canon thought it'd be cute to drop the on-board GPS and WiFi capabilities that the 6D had. I used both of those features all the time. I'm not about to add-on an off-board GPS device (clutter), and I'm trying the Eyefi card for WiFi capability. The card and camera support in-menu enable/disable of the wifi radio on the card, so you can control it as to not deflate battery time of the camera battery.
- It's really big.
- It's really heavy.
If I didn't do large format printing of pics, I wouldn't have bothered buying this camera. 50Mp is just huge and you really feel it when transferring pics (using native SD card slots and of course via WiFi) and importing them into your app (e.g. Lightroom). The files are massive, and rendering software really has to work to do its thing w/ the files. That said, I do print things in large format, and I'm super excited to be able to effectively double my capabilities there.