I have the caseco core360 (magnetic mount) and love it. When I get my pixel I'll probably core a hole through the case so that the case and the little magnet that goes on the phone are flush.
I've tried saying other things, and it's very picky about saying okay Google clearly. I've also tried the 3rd party app Open Mic+ but it's a pain using 3rd party and making sure it's always on.
Can anyone else not stand the phrase "okay Google"? Alexa rolls off the tongue nicely, and okay Google is as far from rolling off the tongue as possible.