I like the idea, but against a deck with Momentum, as other people have pointed out, it will fall flat on it's face if your playing a smart player. Simply play an Armaggio, get it flipped, and be prepared to kill any Maxwell's demon with any splash cards you may have, then momentum your Armaggio to prevent it's statistics from being flipped around.
The best I can think of would be a Gravity/Aether deck to counter this - Use Lightning to kill Max's Demons, Use Quintessence, Universes, and Momentums to utilize the shield to your advantage.
However, you'd have to build a deck around an opponents cards for this to work consistently. It's actually kind of interesting since it seems to provide some form of tug of war between Earth/Gravity/Entropy. Either way, playing this card automatically makes any Maxwell's Demon you have become the highest priority targets.