Shado pan isn't that hard, but it is the hardest for me hands down. I LFR with my 3 DPS and Healer, then run again with my tank and healer. I don't like having to do it twice but I like to perform well and doing it this way really boosts my performance in there. I've never, ever had anyone say or ask if I was multiboxing. I usually am pretty close to the top performance wise, and boxing LFR makes LFR more fun.

One time I said something on one toon, then a guy responded, and I replied on a different toon on accident and played it off by claiming the slave toon was my wife and went to let the cat in.

another time I had broadcasting enabled and ran a slave into the wind lord and told everyone I was very sorry my cat hopped up onto the desk and hit num. lock!

My cat is an amazing scapegoatcat.

Also, it's not really harder to get good numbers out of different classes, it's all about how you have them set up. My Hunter does 200k on Wind Lord (AoE) and he's a slave I'm usually driving from my healer on that fight. My other two DPS are shaman and warrior.