it depends on what kind of beat you want. if i want something that's complex, like if i'm doing drum n bass, OR if i want to shuffle the beat, i create a layer. i find it more intuitive to have all my hats, rides, snares, kicks etc laid out in piano roll form. much more freedom than you get with the step sequencer, and you can see the entire drum track and the direction you're going with it, instead of fucking your brain up with different step sequencer patterns.

But if you're doing a fairly simple hip hop beat or something, i think the step sequencer is faster & easier.