Don, I've had a few of the early ones (DZ-2500a) go out on me, but I like the DZ-2500c flavor. And I totally agree about the DZ-2001 Data Wire Driver. I'm not sure how many DZ-2500 switch machines it will accommodate, but the limitation is in the total length of the bus (~ 75'). I had to split my bus into 2 separate busses. Good news though is that you can daisy chain DZ-2001s. I still have 2 flaky DZ-2500a's on my second bus, but everything else works great.
And you are absolutely correct about saving $$$ using the DZ-2001.
George