Difference between Zoom RFX-2200 and RFX-2000 (also RFX-1000 and RFX-1100)
The Zoom RFX-2200 and RFX-1100 are re-released versions of the RFX-2000 and RFX-1000. The newer versions have combination xlr and 1/4" jack inputs on the front (old only had 1/4" inputs). The new models also have built-in power supplies instead of external transformers ("wall-wart", "line lump") supplies.
Zoom also says the processing has been improved. Unclear if this is the DSP or physical outputs.