i did try playing in a heads-up tournament on
Pokerstars.
20+2 buy-in, 128 people.
won 5 rounds (got lucky at some points...) and got to the semi-finals, and then lost miserably to an ultra-aggressive player, who kept raising me and reraising me, and i wasn't getting much hands so.
at one point after losing half my stack i re-re-reraised all in, only this time he was hlding AK and i lost.
came 3/4th so i got 276 dollars, which wasn't so bad
(but it only made up of for the losses i had that day...)