Between my two tanks that I play i'll list some points about them:

Druid: -Amazing AOE for every trash pull you could dream of. -Fantastic mitigation. -Huge selection of CD's to use for many different encounters. -You get to play a bear that fires lasers... -Enough mobility with Stampeding roar , cat form sprint and charge. -Tons of cc to control mobs, even more so if you play as a Tauren. (Mighty bash, war stomp, Incap roar, thrash slow)

Warrior: -Good mitigation and a solid handful of "Oh shit cd's" -Heroic leap and intercept are great for mobility.( Looks and feels cool ) -Very lacking Artifact ability. -being raged starved is no fun. -Honestly not the greatest AOE either. (buffed currently on the PTR ) -IMO warrior takes a lot more skill to play effectively after the ignore pain nerfs

I won't tell you which one is more fun to play as that is purely subjective. Personally I enjoy both but druid is just in a better spot currently in terms of performance. Hopefully this helps with your decision making.