I'm using an APC 15/6 on my newest 3D plane (YS .91) and it works great. I've been using APC props since a pattern flyer first introduced them to me about 10 years ago, and they've always performed better than others I've tried.

On the big 4-strokes in particular, they (or something similarly rigid, like carbon fiber) are almost a necessity. When I tried a Master Airscrew (nylon) prop of the same size on the .91, you could see the prop visibly warp at about mid RPMs and above, and SERIOUSLY vibrate. I thought it might damage the engine or vibrate the plane into confetti, so I replaced it with the APC, and now it runs smooooothly.

Also, in general, at any diameter I've used, from 10" to 16", they are obviously more efficient, with visible results the first time you fly them.