I'm thinking about replacing my current crossover with one of these.
You don't have to use a line driver between the soundcard and the amp - you can connect them directly. Personally, I want this because it puts everything that I need in the one box.
On top of that, it gives be a volume knob on the dash, which is nice, and also the ability to eq on the fly rather than rely on manky winamp eq bands.
On top of that, Audio Control gear is totally tits.