Heroic Blackrock Mountain down.
Heroic Naxx was easier but this one was hard even with the help of the internet. Almost all of the bosses take multiple attempts and some of the netdecks are just bad or don't work without extreme luck. On some bosses be prepared to make card substitutions to improve your chances of success, no point repeating the same thing over and over hoping for that 1 in 20 chance, try to improve the deck yourself. Some Old Gods cards are breakingly good for some bosses.
Glad I still had my Wild cards too, cards like Kel'Thuzad and Light of the Naaru help a lot in many cases.
Heroic League of Explorers next, anyone done it?