Got my WS-2000 yesterday. I switched the 2000 display with my existing 2902A display, no problems. (I have a another locations that I am going to install the new Osprey sensor and the old 2902A display in). It took WU about an hour before it would recognize the new feed.
The WS-2000 comes with one remote T/H sensor for indoor readings as the T/H sensor is not built into the display. This is a good idea as it keeps any heat generate in the display from throwing off the readings. Also it allows you to monitor a location other then where the display is.
I also got two additional remote T/H sensors and put them in my refrigerators. I was a little concerned with the higher freq of these (I was using Acurite T/H sensors - 433MHz), but both connected and are working fine.
The display is not as big as I would have liked, but is nicer that the 2902A display.
BTW - Ambient now has a iOS app, though it looks to be a simple web client app.