335 ilevel here and still haven't tried a heroic. I'm waiting till more of my guildies are ready.
I hear the heroics are really difficult, like BC heroics! I remember what that was like. I'm not in too much of a hurry to enter them until I've exhausted all other avenues of advancement.
In about a week I should have my weapon from the Tol Barad faction and my epic neck and belt from Ramkahen and Hyjal factions respectively and then, I'll be ready to raid.