To be honest, I was hesitant to do my first few Cataclysm dungeons.
I heard a lot of horror stories about them, and it took me... quite some time before I Q'd up for my very first one, as a tank.
It actually came to be that I didn't start Qing for dungeons until my Tauradin got to Level 80-ish, when I had made myself a set of tanking gear with Blacksmithing. I leveled by dungeons most of the way through Cataclysm, but when I got to 84, that all changed.
The very first "Level 85 Normal" I got stuck into, was if I recall, HoO and it sucked. The difficulty ramped up sharply. Now, that other Uldum dungeon (which I forget the name of lol) was lukewarm in terms of challenge, HoO was boiling hot. I was near-dying on every pull because I was 84 and didn't have very many rep vendor pieces yet. I stopped doing dungeons after a couple of those, and started going back to my solo PvE habits.
Fast-forward until just recently, Firelands and easy 365s, I tried Normals again and they were a breeze, unless I get a newbie healer. Tried Heroics, and they are decent when I actually have decent players. Problem is, anytime you get a sub-9k DPS windowlicker or two, things go to crap REAL fast. Die die die die die....
That's why I haven't done a heroic since a couple weeks ago.
I want those bags, but I hate dying repeatedly. I'm probably going to deck my tank out with all the gear JP can buy and then try again. Maybe by then, the sheer power of 359 with some 365s will help overcome some of the fail I see in the non-Zulian heroics. By then, my Helmet will be the one and only 346 piece I have (well, my Tauradin will also have 346 shoulders... stupid raid token requirement anyways).