I agree about the MPC...I have a Force (because it was cheaper than a used MPC One and more powerful).

But when I don't feel like that paradigm, USB MIdi is not very useful (and of course an MPC can still work with TRS/DIN).

When I want lots of ins and outs, I use a MOTU MIDI Timepiece AV (they're not much more than a decent USB hub and can filter and route and do all sorts of clocking).