Reissue Stereo Polychorus
-uses Panasonic BBD chip
-has stereo outputs. each output is a fixed blend of dry and effected signal, but out of phase with each other.
-has a slide switch to turn on a sweep filter
-tune/delay knob increases clockwise the delay time of the effected signal
-knob placement is different from the vintage unit

Vintage PolyChorus/PolyFlange/EchoFlanger
-uses Reticon BBD chip, which is lofi, and doesn’t get as high delay time as the Panasonic, but has MOJO
-has an effect output and a direct output instead of stereo outputs
-has a blend slide switch to change the effect output from 1) a fixed blend of direct and effected signals, or 2) effected signal only.
-tune knob increases counter-clockwise the delay time of the effected signal

Are they really different?
For guys like me who collect vintage EHX and love to listen for differences, sure, they sound different. They might even sound different to a casual listener. And when using the Reissue in stereo, there’s a HUUUUGE difference in sound. But essentially, both make the same effects.

The Reissue is higher fidelity in the effected signal, has a more fluid modulation, and gets a slightly longer delay time in the slapback. it’s also less expensive to buy used than a vintage unit.

What makes the vintage unit special is the ability to isolate the effected signal using the blend switch. The Reissue can’t do this. Also, the Reticon chips are darker, so the chorus effects aren’t quite as crisp and trebley. Some musicians prefer a darker chorus.

If you like stereo effects, go with the Reissue. It sounds very etheriel in stereo.