I'm a sports photographer for the
College of Staten Island Dolphins. I shoot on both outdoor soccer fields and dim indoor basketball courts. While I've been able to deliver solid images with my K-5 and K-r, high burst rates, deep buffers, and fast, reliable tracking AF matter really to me.
USB 3.0 means UHS-I SDXC slots. It means that the buffer is going to be pretty deep since the data transfer to the card will be fast (and I have a SanDisk Extreme Pro 95MB/s card to take full advantage of it). The AF system is the most advanced we've ever seen in any Pentax DSLR--if the rumors are right (and they likely are), 27 points, all cross-type. The rumors also speak of 8.5 fps continuous shooting, faster than the EOS 7D, EOS 70D, and Nikon D7100.
If RIcoh did it right, the K-3 will set a new benchmark for enthusiast-class DSLR cameras. C&N have finally met their match.
--DragonLord