I think a lot depends on how your kitchen is organized. I have had both methods; I've never had trouble with stuff getting in the slots. Since our wall mount for knives is above the stove (and in the warmer-air zone) I haven't had critter trouble there. Also, for the sake of your arms and pain levels, which is easier to work with? Knives that aren't banging into each other stay sharper; how often do you have to sharpen them now? I have not noticed corrosion on the wall knives, but have had some on the drawer knives (in small amounts) because of dampness not dissipating.
(no subject)