This thread was looking a bit sad so I thought I'd make a post.
Started a HC monk about a week ago (my first HC char) after getting a monk to act 3 inferno on SC.
Currently at level 57 on act 3 Hell and only times I've come close to dying is when getting swarmed by illusion elites, can't escape from those :\
Reason I'm doing hardcore is purely for the achievement points (I'm a bit of an achievement ****) but what I've noticed is that the gameplay is much different from SC in that you tend to play a lot slower and more cautiously and the people in public games are a lot better in terms of communication, skill, patience etc.
Would definitely recommend everyone giving HC a shot and you do get an immense rush whenever you're close to death. Good times...