I used to be a really big Cozy Powell fan. I saw him a few times with Whitesnake, Black Sabbath and Brian May. Live he was great and solid. And a real showman too.
As I grew older and went back to my roots (jazz, blues), I started to find Cozy's drumming lacking groove. I love old school powerhouse drummer, mostly Tommy Aldrdige and Ian Paice. These two were always grooving no matter what. With years, I started to find Cozy's drumming a bit "stiff" for lack of better word.
My favourite drumming of his is on his solo album "Especially You". To me, he showed a side of his drumming that was not seen before, in the sense that it was much more subtle and fine. He was much groovier, adding almost an "R&B" touch to his style.
Regardless, Cozy was one of the greatest rock drummers. He had his own style and sound.