This is a brief review just to state that as with all Yamaha products, the finish and quality is superb. This is nothing like the Schilke 14a4a mouthpiece, which I had hoped it might be, and as such it doesn't suit me that well on piccolo. I do use it, but it is not quite the experience I had with the Schilke piece. Mouthpieces are like shoes - it is very personal, so I will offer some comments on the feel.
The rim is fairly wide and flat with a medium to somewhat pronounced bite. I prefer rounded rims, as such this is one area that didn't suit me.
The cup has enough depth such that you can create a nice full piccolo sound, however, I would reserve this for upper piccolo parts as it is fairly bright. For conservative piccolo pieces I play a Getzen 10 1/2C which has a fairly deep C/V cup and a healthy amount of resistance.
The mouthpiece seems to play nicely in tune, with no real tendency to go very sharp or flat in any register. Some pieces just don't balance with the piccolo, but this does, regardless of the fact that it doesn't 100% suit my face.
I believe Yamaha pieces are generally slightly smaller than the Schilke counterparts, or that is how the perceived feel of the piece and it's size is. This is worth noting if considering a mouthpiece like this.