They cover similar and different ground and can both be as simple as plugging in an input, hitting record, and then looping what you recorded (then overdubbing or depending on the settings recording something completely new). Of course both go much deeper.
Like @yobink said, the Morphagene inherently has an advantage of being much larger- more hands on controls, more modulation inputs, built in attenuverters, stereo. But considering everything W/ can do in only 2hp it’s remarkable.
Morphagene is like having a tape machine with a bunch of shorter (but honestly never feels like it’s that short) reels to chop up and play with, whereas W/ is just one loooooong tape. Even with only 2 modulation inputs, there’s still a bunch to play with. Highly recommend going through some threads here for ideas- especially the W/2 beta thread.
I’d never replace a Morphagene with W/ (not that I think that’s the point) but I love having them together.