All daedric princes can't be applied a good or evil label it dosen't mean anything to them since they are ompiniont beings.
Wow, wait, wait...Daedra Princes are omnipotent? When did THAT happen? I mean, that implies something. Like, all-knowing, all-seeing. I think it would be fair to assume that they are omnipotent in their given realms (i.e. Sheogorath), but if anyone was omnipotent in Nirn, it would be the Aedra - you know, the Nine Divines and such. Which...isn't saying much. If you created something, you well know what's going on in it. Besides, you can generally tag a Daedra with a level of evil.
Mehrunes Dagon = Pretty evil.
Hermaeus Mora = Grey.
Meridia = Good (I think?).
And to be objective, Daedra seem evil, whilst Aedra seem good (though that's a very misinterpreted view). Superficially, however, they do fall into such accordance.