Wait, we aren't talking about with specific setups, or we are?
I have yet to see a commando that I really think to myself "I'm glad he's in our party!" though I usually only see a few of them. Not as scarce as other gunzerkers, but still pretty scarce.
Really though, there are certain bosses where a melee build is completely viable, and thus krieg, gaige, and zero are monstrous. There are others where you can't really use melee at all, and since melee zero and melee krieg only really have that (though krieg can at least throw his axes), they have a LOT of trouble...
Sniper Zero I've never seen used to any great effect honestly, though it could be people missing shots constantly. I've not seen anyone else use bloodlust krieg with a focus on gunplay rather than something else, so there's that too.