If it's going to get wet I say get the commando and buy a spare battery. While the Razr is splash resistant it won't stand up to being submerged in water.
The Commando has the advantage of being a mil spec phone rated for Shock, dust and water resistance.
Even an Otterbox case will not protect a Razr if it gets soked or submerged. How ever there might be some waterproof cases out there for the Razr. Or you could buy one of those waterproof plastic bags that are specifically made with phones/electronics in mind.
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