With regards to raids, I am MT for my raid alliance. We clear labs up to corsolander, but the only reason we go no farther is that we're relatively new to raiding for the most part, and have only just started getting a full x4 raid going. My gear isn't bad, but a lot of SKs on my server and who post here blow mine out the water and several are MT for raiding guilds.
Anyone who berates SK tanking ability is either re-spouting hearsay crap they've heard, has grouped with a crap SK tank once and made a generalized assumption, or rolled a SK and didn't enjoy t1 or t2.