Other converters?
I own the zed-24 and i've used the usb recording and i absolutely hated the sound of the converters i thought it was God awful, but i would definitely buy the zed-24 if you will be using external converters or an interface because i like how the pre's sound. But! if you are...
i had recently purchased a behringer ada8000, which unbeknownst to me needed a toslink/ADAT/Lightpipe input to use the 8 outputs. (it just converts the incoming 8 channels from the toslink into an analog signal which then goes out the xlr outs) i have the digital out running into an alesis io26...