This thing only has 4 things going for it:
3) It has protection against Nobleman Of Crossout
4) It has high defense
Now the bads
1) It being Earth can harm you from time to time if you need a light/dark to remove for the sorcerer (if you are running chaos)
2) It being a warrior may hurt it if Kinetic Soldier or Warrior Elimination rolls around
3) It's effect will have it turned into attack mode after it gets attacked once so it may get you beaten up on more than it'll save you.
Over all I would have to say it's a player choice. I don't use it, but that doesn't mean you can't. Try it out and see if it works for you.