Courier is an ex-pro. You can't get much higher in skill set than a guy like him in his prime, and is still active and successful in post-pro tennis. He was able to wield and use a racquet with one of the smallest heads ever at the top of men's tennis, and able to generate incredible racquet head speed. He swung and met the ball like a bat and baseball, remember? Any idea how hard that is? But I'm getting off the point.
My point is, that means with an 85 sq. in. head he was able to nail the sweet spot over and over and over. So to a guy like him, poly makes complete sense. As long as you hit the sweet spot almost all the time, have awesome hand-eye coordination, and can generate the racquet head speed necessary to get the benefits of poly, ya do it at all levels.
The trouble is, the rest of the world doesn't hit the sweet spot all the time, even with 100 sq. in. heads.
Why would anyone take his opinion on what's good or usable for consumer level tennis? He probably means well, touting the obvious benefits of poly, but come on.
[This has nothing to do with my own opinion of poly, which I may or may not support. I'm just commenting on his value of opinion on equipment for consumer level tennis of 2.0 - 4.0, which probably accounts for most of the regular joe tennis world. If you're an accomplished 4.5+ level player, the benefits of poly in full or hybrid are obvious, if your body can handle it long term.]