Epiphone's P-90's are probably the best pickup they make, I don't know about the Ibby's. The Ibby looks like everything is mushed up on the top instead of spaced about the middle, which makes it look like it's longer then it needs to be. It can be really amazing or completely annoying). The longer length between the trapeze and the tune-o-matic on the Ibby might give unwanted sympathetic vibrations that can be heard through the amp (My casino has this, but it actually makes everything sound like there's a touch of reverb going on. Replacement pickups for the casino are few and far between because of the ridiculous spacing on them, and also because of how thin the neck pickup cover is. The metal covers on the casino's p-90's cut some of the top-end, and make them sound fairly rounded and mellow. This makes it excellent for barre chords and other chord-style playing, or a complete nightmare for solos and leads until you get used to it. It will feel completely alien if you're not used to it.

The Casino is 5-ply maple/birch laminate. The neck joint is deeper set in the Casino than the Ibby, they are going to sound very different because of it.

Epiphone casino vs Ibanez ASR70