The people who live around me swear by the Fly Predators. It is this little wasp that eats up the flies, but doesn't mess with anything else(people, horses, dogs, etc). They do not bite or sting, but they sure keep those flies down, you can tell walking from one yard to the next, who has them and who doesn't.
All the people on my road have horses, so flies can be a big problem when it warms up. Everyone who has tried them, swears by them and uses them year after year.
So I went online and searched for fly traps and ended up on Ridmax fly traps. I was so impressed that I ordered one. If you have one and it doesn't work very well - don't tell me because I already ordered it!
But if you've got one and love it I'd love to hear that!!!