I still use T25. It is old, over 6 years and counting. T25 uses the same sponge as T05 but the bigger pips resist the top sheet from sinking into the sponge a little more. I tried MX-S. I thought it was a little dead and the rubber shrank on my paddle.
I think the whole hardness scale method of measuring rubber is bogus. The ball does not sink into the rubber at a point. I think every one has seen the dust spot of where the ball hits the rubber. That is roughly about 1 cm^2. The rubbers should be tested consistently by applying a force necessary to compress the rubber 0.5mm. Compressing the rubber more, 1mm, would be better but then it becomes impossible to measure a 1mm sponge. There would be consistency and a number, a spring constant, that could be used in simulation. The shore scale numbers don't have units.