i just got the Octatrack for my MPC 3000 and it's really great so far, but i haven't had a lot of time with it yet.

haven't been able to lock the transport controls of the 3K to the Octatrack. need to do some RTFM tonight. that's probably pretty easy to sort out.
the Octatrack on it's own is really great. i love it. using the sequencer is tempting, but nothing beats the 3k workflow for me. i do however want to use the Octatrack for my live shows and have it sequencing my juno / virus. hopefully i can get the transport working nicely so i can record the MPC midi magic to the Octatrack.
the one area of my 3K that always baffles me is program banks. where do you find that parameter? i only get 127 patches to choose from, but not banks.
anyway, if you are looking to kill the laptop in your live rig, the Octatrack is amazing for that.
will report back soon when i get my head around this thing a bit more.