FW? The Orpheus is probably the "best" integrated FW interface available - at least by price. Prism has a cheaper version, I think, since the big O is about $5000. Lynx is next, although their FW is a bit glitchy from reports. I don't know if they still make their FW card, but the USB works good. Plenty of pros use Lynx. Mytek and some of the boutique converters used FW, too. RME is probably the next step down, along w/ TC Electronic. I use the 48, and it has great converters (esp. the DA) and is a complete system; 12 AD/10 DA and dual ADAT and Spdif, surround, DSP. The FW drivers are good now, even if nothing to write home about. There is also the Apollo, which is right in there from what I've heard. Most people can't tell the diff in the conversion between any of those. You need ears, experience and the monitoring environment and even then it is not the deciding factor. Even for lower-priced units. Conversion is really good these days, even for the bottom feeders.
As far as FW itself, it is going the way of the dodo but about as slowly. I don't know about OS's, but if FW is working in 8 (I use Win7) you should be good to go for the next few years. However, if I was buying a top of the line interface I'd go w/ USB since that will still be viable 5+ years down the road. Most mice and keyboards use USB, along with every peripheral, so it ain't going away.
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