Ayup Munky, not sure about exact comparisons as to how much one is better than the other, but the Traveler (god i hate american spellings!) received a very enthusiastic [
review] from SOS. As did the [
Fireface] - much so! The Onyx 400F hasn't been reviewed yet, at least by SOS (although the [
800R] has), but people are seemingly impressed with the audio quality of the mixers of the same name, on forums and stuff.
Now's a pretty good time, technology wise. Thing is, there's almost too much choice.
I guess it just comes down to their feature set(s) and price.
I've plucked for a Traveler as it was cheaper than the Fireface and has an equally decent feature set building on from the Moto 828 mk2, with flexible routing/patching and solid drivers. I'm an enthusiast, not a pro, so couldn't really spend up to the Fireface amount as I was stretching it as much as I could already.
The fireface's soft-clipping would've been ace, though.
Check out the reviews and feature sets, check your budget, and spend.
I certainly don't think you can go far wrong with the RME if you have the cash.