So which is your favorite shifter, and why? do u think digital vs analog makes sense for a shifter comparison, or own both kind of approach do u think ?
-- fzzz

For me, the main two differences between DSP-based and analog frequency shifters are:
1) DSP-based shifters produce aliasing of the high frequencies when shifting upwards. This can of course be a wanted effect. Some VST plugins also have compensation for that: https://soniccharge.com/echobode
2) Analog shifters only have aliasing for low frequencies when shifting downwards. But often, the signal bleed through of the modulating oscillator is a problem. Especially, when I want to use them with delay and feedback.