I have a real drum set at home and all the VSTs I could ever use on my computer, but I often play live and sometimes I don't have a real drummer available. I need flexibility live, so canned backing drums won't cut it. This unit does what I need at a reasonable price.  I'd never record with it and usually don't even arrange full songs with it, but the ability to do A/B patterns, fills, and stop/start with foot switches allows me to extend or cut songs on the fly.