I only use tuanha for ret pally, boomkin and Rouge. I love them all. and yes depends highly what you want to do. I also have BG mate and switch compositions. ret+shami heal, 2x boomkin, Rouge +boomkin. and it's pure fun. Arena runs Ok too but not super great. and if you ever want to switch to PVE you already have everything with tuanha... you can always ask the des for a trail and if you are lucky you might get full feature trail.