I have been researching DSLR's for a while now and I came to a conclusion last fall when I rented a Canon EOS 5D Mark III 22.3 MP Full Frame Digital SLR Camera and a Canon EF 70-200mm f/2.8L IS II Lens that it was the kit I wanted. I rented this set up and used it for the 2-stroke Shootout at Sleepy Hollow. I personally think the pictures came out great! I also used a friend's Nikon D800 (I think) and although the photo quality is great, I found the Canon easier to use and make adjustments to different settings. I also found that the Canon seemed to write the images to the cards faster and not use up the internal buffer. Since I am going to primarily use the camera for motocross events, this was a big plus for the Canon.
I ended up purchasing a Canon EOS 5D Mark III 22.3 MP Full Frame with EF 24-105mm f/4 L IS USM Lens and a Canon EF 70-300mm f/4-5.6 IS Lens. I need a little more time to get the Canon EF 70-200mm f/2.8L IS II Lens, but from what I read, the 70-300 f/4-5.6 should suffice until I get the funds together for the 70-200 f/2.8L. I also purchased a Kingston Digital MobileLite Wireless Flash Reader for Smartphones & Tablets to be able to transfer the photos from my camera & SD card to my iPhone 6+ so I can upload some photos directly from the events that I attend, to Instagram. If you are looking at purchasing any of these products (or anything else for that matter), I have provided links below to them on Amazon. It would be greatly appreciated and will help me get the 70-200 f/2.8L a tiny bit quicker if you would use my links! Oh, and make sure to check out pictures from the Monster Energy Supercross from Met Life Stadium on 4/25/15. I will try to get some uploaded on Sunday the 26th. Follow me on Instagram to see some pics from raceday as the event takes place!