So, in preparation for my move, I went over to the M-Audio site to grab drivers for my Profire2626 for my new Mac (as I've never bothered to hook them up, since I moved right as I bought the Mac). Turns out M-Audio doesn't have a driver for an OSX later than 10.8.4, and I'm running 10.9 Mavericks. Snooping around their customer support site, they have agents responding to user questions stating that "no release date is scheduled at this time" for a Mavericks driver.
So, reading between the lines, I may need to either roll back to an early version of OSX (which a bit of Googling tells me may involve wiping my hard drive and doing a fresh install of an older version) which looks like a titanic pain in the ass, or I need to pony up and buy a new interface, which I'm kind of bummed about because I'm otherwise very happy with the ProFire - it sounds great and it's been perfectly stable.
So, if I do buy a new interface, these would be my requirements.
*at least 4 channels with dedicated preamps
*ability to run additional channels via ADAT, S/PDIF, or Lightpipe
*ideally offering better converters than the M-Audio
Apogee stuff is supposed to be pretty awesome, so the Quartet would be a natural contender here. It's $1400 or so which is, well, more than I'd like to spend, but not out of the question, and it's not rackmountable, which would mean I'd have to have it sitting out on my desktop instead of bolted into a rack - not the end of the world, though. What else should I look at? Also, with the Apogee using Lightpipe rather than S/PDIF, will I have trouble finding compatable preamps to add additional channels? S/PDIF seems to be a little more ubiquitous.
Try and score a used RME Fireface 800? If not, if the Saffire Pro 40 is anything as good as the 24, it'll be right up your street.