I am currently leveling a warrior tank solo. I already have Pally, DK and Druid. I think the simple statement is that dungeons are such a faceroll atm that it is hard to get a good feel for the differences. On most pulls the warrior is decent at holding aggro, no pally but can hold his own. I find I do a lot more damage on the warrior than a lot of the other tanks, he is lvl 77 atm whereas the other tanks are all 80, so no apples to apples yet.
I do like the warrior solo questing in protection spec though, he takes down a lot of mobs pretty fast, so that is nice while leveling.
My gear at present is either the Tempered BS set or dungeon drops, he has 516 defense at lvl 77 (no enchants) and last night cleared HoS in a LFD group, he REALLY suffered in the Bran event with rage issues for AoE pulls but we still cleared it, group was all 77 or lower.