I have both and the waveform on the 2000 is worth its weight in gold,
You can see where to drop tunes and whats going on with the tune in front you alongside the decimal point for tighter mixing,
if you have the funds to goto the top level then dont hesitate as the 2000 is far superior to the 900.
added bonuses include sd reader and hot cues as opposed to slip mode which i dont really use to be honest.