All in all, my preference is for a quick, clean kill, regardless of what sort of critter I'm killing.
I'm less concerned about the ethics of pest-control killing, however, than I am about what is called "sport hunting" for deer, antelope, etc. The first comes under the heading of "necessary chore" and is not the same as "my pleasure in the hunt".
You're from BATFE? Come right in! I use all your fine products!