Bernie, the audio specs are still state of the art, the only reason to change is features.

Bruno, the pcmcia (or pc card) slot on the laptop needs to be type II cardbus (32bit) rather than the older 16 bit spec. All laptops since around 1997 "should" be cardbus (my win98 laptop was where I first used the original indigo) but if a very cheap or old machine check the manufacturer specs.

New laptops now have express card slots which are incompatible with pc card (an adaptor costs ~$100) so unfortunately the echo will one day be joining the pile of obsolete gear, and the usb a/d-d/a boxes used again.