EP-133: 64 Mb internal memory, no SD card slot, 6.3mm jacks, predefined effects (considering the POs these are usually hardcoded with only couple of adjustable parameters), didn't see an unquantizied mode in the manual, but it has note offsets, 9 effects in total, adorable design!
My guess is that EP-133 is very immediate and fun to use but you hit a wall at some point due to lack of storage / limited effects, whereas the 404 will take you from making beats to playing full multi-hour live set and beyond.
Both great in their own right.