My father-in-law has a MyPillow. He bought my wife a MyPillow. He didn't buy me one. That's A-OK.
My wife tolerates her MyPillow. She's mentioned lately that she should probably burn it, considering, but despaired when my last voyage to Bed Bath & Beyond revealed that they're swirling the bankruptcy bowl and have gotten rid of things like... housewares. It's kind of an As-Seen-on-TV store with coupons now. When I told her that BB&B was no longer carrying MyPillow she asked what other pillows they carried. "I didn't see any," I said. Thus, she continues to sleep on a MyPillow.
The principle advantage of the MyPillow is I don't take it and fold it in half when she's not around to take a nap on. The arrival of the MyPillow mostly served to encourage my wife to tell me to leave her fucking pillow alone. She's a spectacular woman with exceedingly simple needs so I don't so much as touch her pillow anymore. The principal advantage, as far as she's concerned, is that it doesn't have a crease in the middle.
I would say that a MyPillow is basically a Tempurpedic pillow run through a wood chipper and stuffed in a cotton bag. This means it is lighter, lumpier and breathes just as shittily as a Tempurpedic pillow. A Tempurpedic pillow, on the other hand, becomes the sweaty thigh of your least favorite aunt in the summer and a wet bag of sand in the winter so running one through a chipper is, I suppose, innovative.