I ended up switching one of my shammies to resto and never looked backed. I also switched from a pally tank to a DK tank, but I went pretty much straight in with craftable epics for the shammies/tank and went to town. Start with Gun'Drak Heroic as I swear its the easiest one in the world minus Eck (Which requires decent DPS) and the final guy who hits like a brick truck.