What is your opinion of this product?
In my honest opinion, there is no better overall interface on the market. If this product suites your I/O needs, there's nothing better. There are other products that people may say have a better sound... but I find that odd, b/c I feel the interface isn't supposed to have a sound. It's supposed to be super clean... and then you can add outboard pieces that have a "sound" if you want that (ie, colored preamps, high end DA conversion, etc). The UCX accomplishes just that, for relatively not so much money, considering the fact that you won't feel the need to upgrade for a very long time.
If I ever upgrade, it will be because I ran out of I/O somehow, and I need to get a UFX.