You can capture multiple streams simultaneously and record only one from your sound card. And of course when recording your stream from the sound card you can't listen to any other music or watch a movie.

When you record from your sound card you re-compress audio files, but when you capture a stream you don't lose any quality.

It is more realiable to capture an on-demand stream, than to record it from a sound card. But here we have live streams.

p.s. You can find this an other information in the forum and in the Streaming media FAQ.