These two extensions do similar things to image gens but Latent Couple seems like it has more options to change images how u wish that's easier to understand. so i got gening and noticed some differences between the two what one excel at. haven't did much testing but i tried to re gen a image i created with regional prompt
using latent couple instead. The image was of a girl with two different eye colors,
its seem latent couple struggles at this particular task. I'm not sure why tho, it seems to handle most complex things pretty well. from my understanding it has something to do with how strong the zones are separated. Regional prompt seems to have a stronger zone separation than Latent Couple has.
This is some comparisons with the image from cover
with out
Regional prompt
Latent Couple
Both