Anyone tried or own this handle? I'm wondering mote about the grips. If the material is spongy or more firm, like some OEM grips from Shimano and Daiwa. 

They're firm, but not as grippy or nice to hold as a Shimano or daiwa knob. They get slippery when wet as well. You can put your Shimano knobs on that handle though of you'd like. I don't like any of the smaller knobs Gomexus makes either, the 27mm TPE ones are great, I also like the 30mm ones and I have a carbon knob that's 38mm I believe which I also like. 

I like the hard aluminum knobs called "feel".

Love them! I have them on my Alphas. They are firm and textured, and feel great. I disagree they are slippery when wet. Mine aren't at all. They spin super smoothly, and feel really solid.