I was meaning to keep my personal views off the thread but I'm giving in.
I have an Atwood tank with no anode rod. My reasons have nothing to do with the dueling manufacturers' chemistry based claims.
1) I sometimes cross-thread things. The design of my Atwood tank encourages this with the drain plug. Cross thread the anode rod and you can ruin the tank. Cross thread the Atwood plug and you can ruin the plug. The weight of the anode rod raises the risk of cross threading even further.
2) Anode rods lead to particles in the tank that can get into the plumbing system and foul things downstream.