I'm telling you again what the Eventide does or doesn't. You can pitch shift monophonic sources perfectly. You can pitch shift effects like reverb or delays: we have an extended library of spcial fx created with multiiple fx going thru pitch shifters for pads, drones and the like. When it comes to chords things may get complex: 4ths, 5ths and octaves are easier to handle. Chordal shifting can be problematic because of different notes and intervals that can confuse pitch detection.
So far I have never heard a pitch shifter changing a dominat 7 altered chord without artifacts, but hopefully one day this will be possible.