I have very strong opinions about outdoor cats. If you live in the country or have lots of acreage then I am not at all opposed to someone letting their cats out. However, my aunt lives in the country with very smart farm cats and they too, were taken by the coyotes.
If you live in the city and have neighbours around you, I am very, very, very opposed to you letting your cats out. My parents' next door neighbours' cats were outdoors and it stank! Our gardens were dug up, both our front and backyards had yellow patches of grass and piles of crap on them. ALL THE TIME!! We'd see the cats all over our yard. They'd fight in our yard, mate in our yard and have litter after litter of kittens in our yard.
We also had a wooden fence separating the properties, they had taken to crapping on the support beams that lie in the middle of the slats. I took out the ladder once and saw as far as the eye, nothing but crap on the fence. We tried talking to our neighbours about it and they were just trashy people. But whether you love your cats or not, you can't control them.
I have my own place now and the neighbours across the street have an indoor/outdoor cat. My cats like to sit on the front windowsill and look outside. Occasionally I'll hear hissing and banging noises, it's the other cat coming to actually attack my cats on my cats' territory! My very laid back, very indoors cat will then try to get out to go fight (even though she's done nothing but live like a queen her whole life and probably wouldn't be very good at fighting).
I know people think cats are "wild at heart" and need to go out, but you need to be considerate to your neighbours too. THEY didn't ask for a cat to roam on THEIR properties when they bought the house. THEY don't want to have to clean up after YOUR cats. Besides, how many times have you driven out in the country and seen a little dead cat on the side of the road? It could've been your cat.