"Live" musicians often push the beat, or lay back from it and what you're doing is using the computer to produce the same effect. We've often used this technique and find it works best on vocals and instrument solos, when it lends a sense of urgency to the playing or singing.

Another thing you can try is moving the snare drum whilst leaving the rest of the kit as it was. Time slipping either way will produce quite a pronounced effect on the feel of the music.

ROG.