It's all about how you need the rubber/sponge to react when you strike the ball. The harder you brush the ball, the harder sponge you would need to get the wanted effect out of the rubber. For me, using a harder sponge, I feel that I'm getting the most out of my rubber with a faster, stiffer blade like Yinhe V14 PRO or Sanwei V5 PRO.
It all comes down to how you hit the ball, and the power and angles you are using. If you feel that something is missing, perhaps you should try something stiffer or faster, but if it feels good, stick with what you got.
If you want to try something else, there are tons of really good blades under $50 to help you discover the differences between all compositions you want to explore.