The pillow and plate use the same charging device; with the pillow, it is just stuck inside the sleeve of the pillow.
That being said, I've used both and I feel the pillow is better because it gives you more surface area to toss the phone on. With the plate, you have to carefully place the phone on it or it will fall off. The pillow gives you more surface area which makes it perfect for a bedside or anyplace else that you may want a bigger pad to place your phone on. The pillow also rattles less when the phone is on vibrate.