I received this bumper today. It fits very well, and as Jephanie stated, the power button covering is tactile. But for me, it doesn't provide a "grip" when you pick up the phone (I usually have mine face down); the only "grip" to it is the power button covering. I'll use it for awhile until I find something else.
My original case is an Incipio frosted back (colors show through), and the bumper part of it has a nice grip to it so that I don't feel as though I might drop it. As rushmore stated earlier about a case, I may drill some tiny holes in the back to provide for more even heat dissipation. My phone has not gotten hot, but it makes sense especially if the phone is put through GPU hoops on occasion.