Sometimes I feel like a lot of us on this forum rely too much on our tools to get the job done. Let us not forget that spin generation comes firstly from proper technique.
I'm not an amazing tennis player, but I can generate just as much spin with multi as I can with poly. I don't know if its an illusion or a fact that its a tad easier to generate spin with a textured poly, but judging by my own skill level, I'd say its an illusion.
when I play with multi, I have no problems generating spin. so if that was my only criterion, I wouldn't select poly for that purpose.