I've been away from 40k for a few years now and I'm mainly considering getting back into the hobby to play with some friends. They typically play WAAC lists so I want to ensure that I'm spending my money wisely. I've been reviewing the factions as I have to 'relate' to the faction in order to be invested enough to built, paint, and the subtle nuances of their play style. I really enjoy my Fantasy Orcs and I'm considering picking up Orks but will need to be competitive against a SM friend who tailors on at least a subconscious level.

So Orks? Or what are the good matchups to SMs?