[Jekyll]

That's true, but you will also win less often. Suppose you're 60% to win in any given HU match. You will be 36% to win any given 4-man HU. 60% of 2(buy-ins) is 1.2, and 36% of 4 is 1.44. So ROI is .2 and .44, respectively, not counting rake(just subtract .1 for 10% rake). And if you consider that you can play 2 separate HU matches back to back in the same time as a 4-man HU, you can call them .2 and .34 respectively.

So the 4-man HU is better, but it's because you are effectively paying half the rake to prize pool ratio you normally are. The difference is slightly exaggerated, b/c the rake is large chunk of your initial profit at 60%, but even larger win percentages still display an advantage at 4-man, when I ran the numbers.

There appears to be something else at work here, too, other than the rake. I think it has something to do with your equity when you start out in a 4-man. You start with 25% equity, with 25% of the chips in play. If you lose the first match, you lose that 25% equity. If you win, you won 25% more equity, so even if you lose, you had an average equity of 37% per match. This is as opposed to a 2-man HU, where every time you lose, you lost your 50% equity.

Comments? I know I rambled a bit, but I think that was valid.