I have played with both. PK50 is an excellent forehand rubber for a short period and then the grip fades away drastically and it starts to behave quite hard and without any feel, i.e. you would have to put a lot of effort to engage the sponge, but this deadness is quite different (and not in a good way) than the hard Chinese tacky rubbers such as Hurricane and Battle 2 (I have played with them for quite a while), I bought three sheets of PK50 one after another because I really really liked the first few weeks with it (I play perhaps 4-6 hours a week) so i kept trying, hoping that it was one of those bad batch, but unfortunately all three of them showed this characteristics. In another word, I would say, don't bother this rubber, pick something else, such as Rasanter c48, a very nice rubber with a little less rotation.
I had one pair of Rakza Z, which I used with a carbon blade (Andro trieber CI Off), I felt I could not control the ball so well anymore, So i did not used it for very long and moved on to slower setup. Now I feel that, I should have tried it on an all wood blade (same blade, which I used for PK50) to compare it better,