The list is... ?
1. S/PDIF ports only work if it's the only device on the FireWire bus. That's input
and output, so you can't even get another device to lock to its clock unless you fool the M-Audio device by sticking it on a separate FireWire card so it thinks it is the only device in the world.... I suspect this is a driver bug related to isoch reservations, but I don't have time to debug their drivers for them....
2. Their Mac drivers broke for me on almost every software update during 10.3 and the first part of 10.4 until I finally gave up and rolled back to a version prior to when they added Pro Tools support. Those versions kept working from then on, and I haven't touched them, but I haven't used it in a while, so it might be broken again by now, not sure.
3. The hardware is too big to fit on a rack shelf by about a quarter inch.
4. Their drivers really suck. Because they feel the need to keep supporting 10.2 (why!?!), and because they don't know what they're doing, instead of writing a legitimate I/O Kit driver with the old 10.2 version at the top level and newer versions for usable revs of Mac OS X in a sub-bundle with different version dependencies, they instead chose to do this crude hack using a startup item with a shell script that loads the right driver on the right version of the OS. This means:
a. Their driver isn't fully hot-pluggable. You have to reboot for the device to show up correctly if it isn't plugged in and turned on when you boot.
b. Apple's driver
does match and mostly works (with recent firmware), so the only way you know that you're using the wrong driver is that you can't adjust any of the device settings except for clock rate. Oh, and you also notice because the device suddenly works better than it did with M-Audio's drivers....
c. They leave this daemon running in the background to unload and reload if the device goes away and comes back, so you're wasting CPU resources.
5. Did I mention the driver sucks? Weird glitches where it plays the same chunk of audio over and over again, halfway freezing the machine while it does, dropouts, kernel panics, etc. seem to plague this driver. Once you find a version that works, I just recommend never upgrading your OS again. It's that bad.
6. Did I mention the driver sucks? I'm pretty sure the CPU utilization is higher for this than for both my 8Pre interfaces put together.
7. Then, there's the hardware. It's as expensive as a MOTU 8Pre but has six fewer pres (which IMHO don't sound as good), can only do 48 kHz ADAT (or 96 kHz with half as many channels) instead of 96 kHz, and really doesn't play well with any other interfaces.
8. I also found its ability to lock to an S/PDIF signal was pretty dicey. It worked most of the time, but it seemed to be pickier about the quality of the signal than other gear.
If you need more reasons, I can probably think of a few more, but those were the most obvious ones. The only plus side is that it has two more audio outputs than the 8Pre. If that's important, though, I'd point you towards the MOTU Ultralight. It's basically MOTU's answer to the FW1814, minus the optical, but with more outputs, much better on-device metering, independent phantom power control, built-in pads... basically the sort of niceties I've come to expect from MOTU's hardware.
