I’ve had the 2000 and 2500 before.
The lack of pads is the most obvious. You can get a pad controller or Rytm.
Note repeat is different. You have to dial it in on OT.
You get Chromatic on OT for MPC 16 steps.
I think the MPC has a better midi sequencer but the OT is better at sampling.
I think the MPC had a good reverb. The OT has a better filter and more effects in general. You can map samples on the 16 step grid on OT like the pads.
The OT is newer, it’s going to be able to do more. You never really have to stop the sequencer to do anything. I remember having to stop the sequencer on the MPC to access some features. You can watch the OT sample buffer filling up as you record. For live sampling the OT wins. For slices, if you set your buffer slices in the current BPM, you can always slice any new recording with predefined sample slices on the fly. I don’t remember messing with sample rate on the MPC. You can do this on an OT to negative rates so it plays in reverse. You can route your sample playback to re-sample any track on the fly. I don’t remember the MPC doing this.
The MPC has more midi i/o, more audio out, but less audio in.
I got tired of the MPC, I had the 2000 for a long time. I also got tired of a MD. The OT seems to do much more imo.
Once you get used to the machine, the OT has a better work flow. You never have to stop it. The access to the sample memory is light years ahead.