The dimidiochromis compressiceps are awesome fish, and though they may not look it, they are quite peaceful, and way less aggressive than most people assume. They can also gain incredible iridescent color upon reaching maturity.
Keep in mind however, these fish are hunters, and therefore have been known to eat any fish they can fit in their mouth! I've actually heard of some people using them in the past as a "natural population control" to keep the more rapidly reproducing malawis under wraps. I suppose this may or may not be a desirable side effect of keeping comps depending on what you're doing with your setup! Either way, their stalking behavior is great fun to watch! Enjoy them!