just to echo what george2loose said about how deep stacked the pokerstars tourneys are.......
i played in one not so long ago, on a saturday night.
$20 +$2 buy in....450 players and it started at about 11.15 pm.....i went bust at 6.30 am and came in at 24th i think....
there is so much room to try different styles and tactics, and get a feel for you table. I reckon if it was not so late (or early) i would have done better.
As a side note, iv also seen chris moneymaker playing in these.....lol.