I use Equispot and it works pretty well for ticks. The only other thing it seems to help with is black flies/gnats, but I live in a high Lyme disease area so I keep Equispot on him as long as there is no snow on the ground.
I do notice that some horses are bothered by it. They all seem to get a little fussy when you put it on (I'm guessing maybe it tickles or feels weird as it trickles between the hairs?). I had one Thoroughbred that it burned the hair off of though. That seems to be relatively rare.
I got all excited when I first saw the Freedom 45, thinking they had come up with something that lasted 45 days, so I was bummed when I saw it just referred to the percentage of permethrin.
Yes, I forgot, it does help with the gnats too, and saved a gelding I had with mild sweet itch. I did have one horse have a reaction to the equi spot, and lose a bit of hair, but switching brands fixed that for him. I sure do wish it lasted 45 days!