Another vote for Sawyers. It is a little expensive, but I haven't had a tick on me in years. I've hunted alongside buddies who've peeled numerous ticks off them when back at the truck, while I had none.
Another thing you can do is shed your clothes as soon as you are out the field and put them in a trashbag. Once you get home, throw them in the dryer for 30 minutes. The heat will kill any ticks that might be in/on your clothing.