get the 2500 if you can, right now there's not enough test done on it to see what bugs fixes are need. 1k is updateing it's bug fix which will be compared to the 2500 without the grid-midi-input-output-things.Check out
these to compare.
http://www.mpc-forums.com/viewtopic.php?t=38069/MPC -1000
http://www.samplekings.net/mpc2500_preview.htm
http://www.futureproducers.com/tutorial.php/id/41
there both good machines, one is jus for studio and the other can be used for portable transfer ,carry around type projects. T"