Well I think it sounds better.
It has 9 inputs + 3 tuners + 1 local input per zone, so thats a huge plus over Nexus' 5 inputs + 1 tuner

You can have more zones, and all will be using the 60watts per channel. Nexus only offers the 60/ch for the first 6 zones.

Any zone can also feed into a separate power amp. Nexus requires a high level>line level adaptor. With the B&K, you can have the speaker output be variable, and the line level can be fixed OR variable.

You can set zones to run in mono which is quite useful in some applications.
If you run a zone in mono, each channel can actually become a separate and independent ZONE !


The Nexus has its place though:
Very easy to setup and install, and no programming (other than the basic learning of IR commands).
You get Tuner Freq and Volume level feedback on the keypads. (this is also possible with B&K if you use the B&K keypads, but I don't)
Sometimes, I just like a small (decora) keypad. And the Nexus has one of the nicest looking.
However, when the RK1 finally arrives, it will be huge for us.