Tethering w Nikon D810 vs Canon 5D3 buffer + speed?

I own a few Canon 5D3s in my kit and have been mostly happy with the performance with tethering, although for some shooters the buffer will get full rather quickly. Have considered investing in the Nikon D810 and know that the files are bigger, but it supports USB 3.0 tethering, which is much faster than USB 2.0.

Does anyone with actual experience with a D810 and a recent Macbook Pro Retina (mine are all i7, SSD, 16GB ram, USB3.0) have any feedback regarding the performance with C1 8.1? Are there any bugs that need to be worked out or is it stable at this point?