Well, I did a bit of poking around for posted comments on the quality and sound of the M-Audio Fast Track Ultra 8R, and found a mixture of good and bad thoughts on it.
The product seems to have a whole new chip set from the non-Ultra Fast Track, which was done as part of an upgrade to support USB 2.0, according to M-Audio comments.
A lot of folks seem to complain about the customer service of M-Audio, which was exacerbated by multiple shipped units having non-working or broken parts, and a reportedly horrendous amount of time for RMA processing (getting a replacement unit shipped back from M-Audio took forever, it seems).
Here are some comments from one of the M-Audio folks on the Ultra:
"Hey guys, RayT here. I'm the Hardware Product Manager for M-Audio. I've only been with the company for about 1 year (I was with Mackie before this) so I don't have a ton of info on our legacy products. I did directly manage the Fast Track Ultra and would be happy to answer any questions you may have.
To start, yes the Ultra is a completely new design compared to the Fast Track Pro. The chip set used is entirely new in order to get the higher performance and USB 2.0 functionality. The preamps are based on the Octane design but have been enhanced with newer technologies for better performance.
The SNR for the preamps is -103dB and there's about 53dB of gain range (from +6dB - +59dB) without the 20dB pad. The Headphone amps have also been re-designed to offer more clarity and power. The line inputs were designed to bypass the mic preamp so you get a cleaner, more direct signal.
We also spent a lot of time on the new USB 2.0 drivers so they are very solid and reliable.
I don't expect anyone to trust my word on the products as I work for the company. I strongly encourage open discussions here on the forums and trying out the gear for yourself.
RayT"
Other than basic issues, such as the quality of the build and the stability of the drivers, the pieces that could be problematic would potentially include the quality of the pre-amps and the converters. Some folks liked the pre-amps and the converters, and some thought the pre-amps were noisy beyond a certain level.
I would suggest you do a Google search for reviews of the interface, and of any other ones you are considering, so that you have a better feel for what you are in for, both good and bad, for whichever interface you end up choosing.
I feel the better the research, the better the outcome of the decision.
Good luck,
Bob Bone