My big one is reliability. It has to be dependable or it's just an anxiety generator.
If it "Limpwrists" after it gets broken in, it's gone. If it's a 1911, I pass it up, if it says "GLock" on it, I walk on by. Same goes for most all Polymer guns, regardless of brand. I do own a couple, but even the best one, by a mile, a custom CZ-P07, doesn't do much for me in the way of caring about it.
If it's a steel CZ or clone, I say, "Hi there!", Same goes for Beretta 92's and clones, and Sigs. I like them a lot.