Just purchased some to use for the first time this fall. Your thoughts on them and anything negative about them.

I've used them in the past for cats, and really like them. They conform to the pan nice with no raised areas and the rest of the cover lays flat. They do give off a slight rubber scent, which may turn coyotes off...I have no idea if that's true or not, just a thought. The one downside is that they are expensive if you're going to purchase the pre-cut packaged ones from the supply houses. I have gone to landscaping fabric. In the spring time, you can purchase two rolls for the price of one at the local big box home improvement store (reg price $6.00/roll) and get 500 pan covers out of one roll. These would be 6x6 size. 500 pan covers for $3.00 is hard to beat.