The sample decks and loop recorded sounded quite cool before i actually got my S4. But i've never bothered learning how to use them, nor do i want to trigger a load of one shot samples. Seems more suited to 'controllerism' type DJ's. I gotta say as much as i don't like ableton for DJ'ing, and think serrato looks a bit naff, the whole 'Bridge' thing is a really cool idea. The whole S4/Traktor 2 thing seems a bit strange to me. Makes you wonder why they even bothered with it in the first place when it was intended to be dropped within 6 months. Almost as if it was a feature stripped Traktor 2 that was stuck together for the S4 release.
Its rare I use the loop recorder for fear I f*ck up during a mix. Samples Ive used a few times only. I really need to play with them more