I haven't used either of these so I can't really give a comparison. I can only give my experiences of the one I've used. It's fairly basic, not a whole lot to play around with--although I'm told the Mac software is pretty nice (but I've only used it on a PC). Anyway, we wanted a very reliable, small and compact unit that could be put in our test kit. We wanted it to measure very very close to flat (although our software doesn't actually require very high performance of a sound card). We did measure the card and it's very flat. I have played music through it and it sounds far far better than the stock soundcard (but that's not really saying much). I have not recorded on it, but have spoken to a few people that have and they were very pleased with it. We work with some professional groups and have thought about taking the PC and recording some things on it--just haven't gotten to that yet. Now ESI does make some more sophisticated units (we don't sell them) but I imagine they have just about anything you could want for more serious recording. You can visit their site at
http://www.esi-pro.com/