why so many benchmark dac1's on audiogon?

I am looking to upgrade my digital front end

my phillips transport Audio Aero gave up the ghost and is too expensive to fix

I bought a nice audio research cd2 - may use it as a transport

I eventually want to go to an alesis masterlink or tascam or other and do 24/96 recordings off my analog rig

I read the sterophile review, see a lot of the benchmark dacs here on audiogon.

I would be interested in the usb version
the pre isn't going to be as good as my dedicated pre

any comments on why there are so many on audiogon?
good sources to buy from?
would want cd and usb inports

I'd prefer the black model