I haven't spent any time with the Map-Pod yet (wrote about it a few months ago) but a couple of us are in the queue for one (that means you, G). In the meantime, here's Matt from Down Range Firearms Training giving us his opinion of it. Unless something is really really squirrely with it I will probably be buying a few when they're available. My only question at this juncture is how they will affect a closely-packed rig (which I'm betting someone will address in this thread in short order).
I should say this - I fall firmly in the "It's okay to rest the magazine on the ground" camp, with or without a Mag-Pod, terrain allowing. Obviously there will be those who disagree with me, but I figured I should be up front about it.