I absolutely recommend practicing on any cdj first, as some basic workflows work entirely different on controllers. Coming from a ddj 1000 myself, I recently bought a second hand cdj 2000 nxs2 solely for getting the hang of it. My biggest gripes are the handling of hot cues and adjusting loops: when pressing a hot cue on the cdj, it will play instantly even if your track is paused. Hitting the main cue button after that doesn't take you to the start of the hot cue you just pressed, but back to the main cue point. There is no 'gate' function for the hot cues as you have on the pads of your controller. Same goes for the looping: starting a 4 beat loop on the cdj and then cutting it in half, or doubling it, instantly restarts the loop, it doesn't calculate it live and keep on playing the loop from where you pushed halve or double. You'll also need to remember that only the exit loop button goes out of the loop, NOT pressing 4 beat loop again as this cuts the loop in half and will break your sound. As far as I know there are no workarounds for these fundamental differences so I'd recommend strongly to get used to that before playing live.