The MPC "can" do it too but it's such a headache to even try to do it. The MPC pads are mapped in such a way that it's VERY difficult to get the right note mapped to the right pad, and have it as a playable patch from a MIDI keyboard. The ASR-X pads are already mapped like a keyboard so it's much more intuitive. The sample can be set to loop seamlessly, it escapes my memory at this precise moment, but I have done it before with a rock guitar patch I made. Of course most of my patches I get from other sources like Akai S1000 sound discs, Ensoniq EPS and ASR-10 disks. Or downloaded from various Ensoniq sound sites.