The synth stomp boxes in general work pretty well so long as there's only a single fundamental (note) that has to be picked up, but they don't do well with chording.<p>The advantage of the on-board pickups is of course having one pickup per string, but also that they're designed with a specific signal profile in mind (i.e. how far those pickups will be from the strings) and with the dynamics of that instrument involved (i.e. the difference between picking up a signal in an electric bass vs. a flute).