Deosect, by far. A 250ml bottle makes up the equivellent of about 25 bottles of the stuff you buy at the tack shop and at £28.00 that's a saving of about £180.00. You do have to dilute it properly as it is very strong and will melt through plastic if left neat, but it is great stuff.
We use the Deosect stuff, feed garlic all year round aswell, when we run out of fly spray we find that diluting vinagar and spaying it on the horses works aswell
I went to yard to check merlin tonight and he was really distressed with flies crawling all over him..... He actually looked pleased to see me (till he saw the muzzle)!!
I sprayed him with powerfazer and all the flies went away .... onto his field companion
So I gave him a little spray too.... and they were all but gone then.
Havent rated it much previously, but boy did it make a difference tonight!!!