Hey,
The MPC is a combination hardware sampler/midi sequencer/pad controller.
Battery, to my knowledge, is a software drum machine emulator. Obviously it lacks the controller, and I'm sure that without an ASIO soundcard it doesn't work in real-time as well as an MPC would. It probably has a step-time sequencer or something to that effect, I don't know if you would be able to trigger its sounds from an external controller.
Take care,
Nick