Devastator:The strongest tank in the game. However, it turns very slowly and it's just all over SLOW. The Devastator does have a pretty good weapon, and a self destruct option, though.

 

Death Hand Missle(DHM):There are two bad things about this:It's not accurate and it has a small range. The two good things are it's very strong and it almost always destroys a building.

 

Those are the differences of House Harkonnen.