A/D D/A While I don't have a ton of experience with converters, I immediately noticed how good the conversion was when listening to music on my computer. It's simply light years ahead of the onboard sound card. Even music streamed over the internet seemed better defined and clearer, though this did expose how compressed the high end is in streaming music. It's conversion was equally good when running a guitar direct into it and through an amp simulator.
Preamps The preamps on this interface are a great value for their low cost, and they are quite clean, however they do add a hint of character to the sources run through them. They seem to add a mild punchiness to anything recorded to it, which suggests a slightly boosted mid range. However, this isn't the the point where it becomes detrimental on some sources. The rest on the frequency range seems quite true to the source, and I've been really happy with the early results I've had on vocals and acoustic guitar. The preamps also do have quite a bit of gain available, and I've been able to get a good level with my active ribbon microphone Blue Microphones Woodpecker Ribbon Microphone Kit by turning the knob to about 2 o'clock.
The Unit Itself The build quality of this unit is excellent. Though it's made of plastic, it seems very durable, and is pretty heavy for it's size. (It's larger than it looks in the photo, about a foot long and about 4 inches tall) The knobs all turn slowly, and feel quite solid. They also are fairly large, and spaced far enough apart that you won't accidentally change the wrong one. All of the inputs feel solidly built as well, which is reassuring in regards to this unit's lifespan. My only gripes about this is that they could've put db level markings around either the knobs or alongside the level indicator. The unit looks awesome and the leds for input and output levels are a nice touch. Though I don't sit it between a keyboard and monitor like Lexicon recommends, it fits well next to my laptop.
Latency Of course the latency of an interface and turn a phenomenal unit into a paperweight, but I happy to report that I've been able to achieve quite low latency (19ms roundtrip) on my 2.1 ghz, 3 gb ram laptop. This allows me to record guitar through amp simulators, and do midi work with ease. Response on both guitar and soft synths controlled by a midi keyboard is pretty much instant, which makes it really easy to work with.