I am a big fan of tournaments, but more often win in cash games than in tournaments. Cash games look to me more as games of skills compared to tournaments where people because of the large blind sizes start to shove with everything. Anyway, the question is which one is more profitable in terms of money for a decent player?
The more profitable is the one that you're performing better.
If you have the required bankroll, you have to venture into all game types to see where you perform better. This is debatable, but you should not listen to forum discussions about this topic as its per-opinion; Everyone will say what's profitable to him and his own skill level.
Some say its cash but rake kills it, some other say MTT but the brutal variance kills eg. You have to play lots in different game types to find where you belong.
If there was an easy answer to this, i believe everyone would play that game.