well the reason why serato (and the older Final Scratch) were hits was because of teh Control surfaces being CDJ-1000 or specially made vinyl...
I've never tried any "software-mixing" as I love live looping, quick reverse, hot cues, and the pitch slider (and jog-dials) to control my mixes.. ohh yeah and effects... everything should be a button, switch, fader or knob (no pun intended!)
with a laptop-only solution it's just the computer keyboard that is not as heavy duty as the CDJ's "play/cue buttons... smack the buttons.. then try applying the same pressure on your laptops' space bar.. what feels more likely to bust?
sorry if the video is too big for most Lebo-Connections... (Dolphina on Dial-up

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