It depends CNC3 has unlimited units and it works well, Think though... in a real setting would you have a cap on units to have brought in? "I'm sorry commander were at our max limit!!" just does not make since to me. About playing 6 comps, haha better have a good def

Just think you could have 50 tanks with air support guarding your base. I know you think that it seems like it would not fit into the game well b/c your used to a 200 max. I know that in most sc games I try to make a bunch of differnt types of units but, find once im maxed I cant make the extra units I will need to plan a good attack.
Say im playing Protoss against terran. I am maxed with nothing but dragoons pumping into a guys base, but I realize that I need to make arbitors and temps b/c tanks are owning my dragoons... Im maxed though what can I do to solve this?? well I would have to cancel all the guys building in my gateways and make Arbitors and templars, which in turn stops my flow of dragoons into his base to build tech units... I mean I do this now and usually win but, if there was no max on guys... I would not have to ever worry about ruining my mass. It would make for a much funner battle in my mind. Cuz you can anticipate your enemys move and prepare for it with out worrying about slowing your flow of units being made.