There are moments when you are allowed to feel good about yourself and this is definitely one of mine; having completed the Tribute to Skill achievement on 10-man totgc instance this evening, with an awesome crew. It was particularly satisfying after having endlessly farmed both 10- and 25-man normal modes with little to no challenge of feeling of accomplishment.
Grand crusader however, was quite a struggle. The encounters we found the hardest were the Faction Champions and Anub'arak. The first severely more than the last, where the champions just simply kept wiping the floor with us. Anub'arak proved mainly a performance challenge, as it has a lot more in-built difficulty than the normal modes.
Firstly, you only have six grounds of frost to use, the burrowers now cast Shadow Strike that needs to be interrupted, and the damage is a lot more severe. The two primary obstacles are performing successful interrupts and keeping them from burrowing. We used a shaman, though a rogue would probably be a lot more optimal, with a focus kick macro as the adds and boss are tanked side by side.
It also comes to a bit of luck, when Anub'arak himself burrows, the OT will most likely still have two adds on his hands. Because the proximity to the boss, the spikes will probably hit the ice he is standing, breaking it, possibly even killing the OT if he is not maxed out. The OT must vacate the patch of ice before the spikes hit it and kite the adds to a new one without letting them burrow themselves. Since this ability is on a timer, it is has a lot to do with luck.
However, if you can master these two aspects, the fight should go through fairly easily. The only crunch is when phase 3 starts and the OT is not only taking the constant aoe damage from the boss but also melee hits from the adds.
But the fight is well worth it, even if you have to struggle. I had the luck of getting Lothar's Edge, hitch hiking my stats up a notch once more. So for now, I could not be happier but am already looking for the next peak to climb.