As I said early on, I only chose 5 from the same manufacturer because it was the easy way out. However, I can think of one time you might actually do this: in the research stage, when you would go to the manufacturer's website (and the reviews at vendors and backpackgeartest) to see which, if any, of their tents you might want. You'd then end up with, say, one finalist from MSR, one from BA, one from Tarptent, etc.