Agree with the above - Used most to razka rubbers (I have Razka 7 soft, 7, x, z, tried briefly xx and 9).
9 is the fastest but harder to control in short game as catapult and bouncy
7/7 soft is one of the slowest (allrounder) and easiest to control,
x is quite low throw but very linear and one of the most balanced rubbers,
xx is slightly faster and slightly higher throw than x - slightly less control,
z is very spinny and heavy and highest throw (alternate to dignics 09c but slower).
I like x and xx the best, 7 is great allrounder but I feel slow on a wood blade - seems to be better on a faster carbon blade . Z is not spin sensitive but must put on right blade (works well on yinhe pro 1, timoboll- on stiff carbon blades with heaps of control). On wrong blade it can be very high throw (FZD)- over shoot the table. On the right blade its great. Hope that helps .