Yey, had a good night in Ulduar. Only 2 bosses down, we had 3-4 tries on Iron Council, then I decided that I was better suited for add-tanking, and the OT better suited for Steelbreaker. Situational awareness and all that.
In general I have found Ulduar to be much more demanding on the offtank, a lot of movement, a lot of spatial awareness. Offtanking on most encounters in Ulduar (that I have tried) actually demands more from the offtank, than from the main tank.
Anyway,...