Softer sponge enables better grip on to the ball. I have the Bluefire M3 on the backhand, and it grips the ball amazingly which generates very good spin. The low arc of the topspins generated also helped a whole lot as they proved very hard to be returned by my opponent.
This is a very spinny and fast rubber. Very close to Tenergy 05 in my opinion and a possible alternative. I think this rubber is a little faster and much more spinnier than Tenergy 05. Highly responsive is a word, I would use. It would hence help all your aggressive shots a lot, while it is slightly hard to control block and short service returns, initially. This is an advanced rubber in my opinion, just like Tenergy 05.
Donic Bluefire M3 Rubber -