According to a review on a hungarian forum: very porous white sponge, elastic and soft. Topsheet similar to Acuda series'.
Uncut weight: 70g (max)
Warm up drives: A little slower than MX-P and a little lower arc. Not too much catapult effect.
FH Loops: Low arc from any distance. Quite easy to loop, but it lacks spin. With more power becomes really fast, but spill not too spinny. (average spin)
FH block: safe, but you nedd to block actively. Not spin sensitive.
BH: Easy to loop (easier compared to MX-P) and the reviewer was able to generate good power. Better on BH than MX-P.
Reviewer recommend this to aggressive attack players who likes to hit the ball hard. Compared to Bluefire M2 it's faster and has more feeling.
I just translated and summarized (but contains all the important informations) the original review, didn't used the rubber. Hope this helps!
[EDIT: this is for the normal Quantum, not the S. The S version is slower and softer]