I have an older version of the Ettus b200. I forget which chip it uses. It's always a PITA to first get it to work the first time, but when it works it is awesome. Simon will comment on the issues with the Ettus firmware.
I just fired up the b200 and Simon's latest V3 code. All is working smoothly monitoring ATC stuff.
Remind me how you check on the Ettus firmware version, and I'll get back to you.