I have 10 horses (5 mine, 5 boarding) and use fly sheets and fly masks on all of them. Horses are a lot more comfortable and I need only a fraction of the insect repellant that I used before. I figure that over the course of the first summer, I paid for the jackets by the savings on repellants.
Looked at a lot of options before buying (see http://wowhorses.com/horse-fly-sheet.html ). For maximum protection I got the neck covers, belly covers and head covers. Have one horse with a major sweet itch problem, wished I had got a tail cover for him.
Fly Sheets - By Doug Stewart - 









