It looks like a nice little invention that was just waiting to be discovered. The only thing I wonder about is whether resting the rifle on its magazine could cause some misfeeds. This may be a non-issue and one that Magpul examined and then discarded as irrelevant.
UPDATE: According to Rob Curtis at MilitaryTime's GearScout blog, he was concerned about the same thing.
I was surprised that shooting from the mag had no effect on feeding/cycling on either AR used during the evaluation. The first rifle was a Smith & Wesson M&P15 VTAC and the second, a Mega Arms lower with a Daniel Defense 16” upper. Both cycled flawlessly with the MagPod. I was so determined to cause a malf, that I sat on the range dumping rounds ‘till my right thumb was sore from loading and my left hand was sweating from the smoking barrels.I guess that answers my question - it doesn't cause misfeeds. Read his full review of it at the link above.
I thought this floorplate was from Magpul itself as it was designed to work with their PMag. That is incorrect. It is from the same company that makes Multitasker Tools. They are out of Marietta, Georgia according to their Facebook page.