I have bought a octopre LE from ebay - and realised that I need something better than my lexicon omega to get all 8 mic inputs working at the same time. Especially as separate audio streams.
I have 2 laptops to work with, one with firewire and the other with a firewire card, so USB or firewire are both good. And it needs to be inexpensive…
My vote would be for something like this…
I use them for theater sound and they have been very good interfaces, plus Echo has been working with Pieter on FFADO to get these working, I would check with them to see the status but I believe that they are working fine is what I heard I thought.
If you want better quality go with RME.