This is a good question, one that really does not have an answer. We can argue both sides of the point as to which requres more skill. Poker is a skill game with the luck factor sprinkled in good and bad from time to time.
It seems most here see heads up as the end of the game scenereo. The final two of 9 or 18 or hundreds. We should realize it is also a game in itself. There are two distinct games here, both requiring poker skills, all of them.
There is a big difference playing heads up where second place nets a nice payday versus nothing in a one on one match. When playing for hours and down to two you tend to play more aggressively, you are in the money and in deep. You may and should already have some feel and reads on this player. In a one on one match unless playing previously you must sit opposite this player and learn things on the fly with no consolation for a mistake.
I think this is a good question, like I stated before with no real answer. Great for debate. They all take skill, now go out and win some cash in what ever game you enjoy.
Later,
