Originally Posted by
Shelly
They are all super viable and incredibly close in terms of performance.
If you are playing casually - as in just heroic raids, maybe a few mythic raids and mythic+ of any level - then there's not much need to pick a specific one.
If you're going for something super competitive though then you aren't just looking at yourself but building a team and your tank choice should be based around your other team members.
That said I think DK is the best all-rounder for M+. I think it has the highest dps, grasp is amazing for engineering large trash pulls, the self healing is fantastic and you always have some sort of AoE up for aggro.
Warriors are also in a pretty good spot with rallying cry and a solid choice between dps and survivability in the talent options and probably the best mobility in the game right now between charge and leap.
The best thing for you to do would be to hop into some random heroics or look for some mythic dungeon groups and play each then commit to the one you like best. Or just play them both, Legion is in that spot where you've got a lot of leeway for alts.