I use mostly styles, a couple of midi's and MP3 too. My wife absolutely hates midi files and karaoke tracks. She likes to be able to stretch sections, or sometimes just have the drums play as she loves to dance and get people up and dancing or even vamp as we figure out what we're going to do next ... . We are always playing with different combinations of musicians, some of them can really stretch a solo very nicely. I'd hate to cut them off, just because the track is about to end! I know there's ways of manipulating midi files and audio tracks, but I haven't gotten around to learning that yet, as styles work for most of the stuff we do anyways.