I'm testing out Nikon's D500. With 10fps and the focus engine from the D5, it should make an excellent wildlife camera. It's miles ahead of the D300, D700 and D800 in focusing. FPS is close in performance when compared to a battery gripped D300 and D700. IQ is better than the D300. IQ is about the same as the D700 except for having the ability to crop more when needed. The D800/810 has better IQ in good light. In low light, the D500 is on par with the D700. I think the D700 gets a slight edge. The speed of the D500 is amazing.
One thing I was wondering about was the speed difference between the XQD and SD card slots and associated memory cards. I wanted to run the D500 in backup mode. However, the speed difference is crippling. In backup mode, you only get a 35 shot buffer. Not the 200 shot buffer you get with a single XQD card. I wish Nikon had just gone with dual XQD slots. Still, it's not a big enough problem to make me give up the camera. The speed and focus accuracy are still the best in class.