Yes it works.
I treated my clothes and backpack prior to my last overnight hike in FL. My hiking partner did not treat his clothes. At camp, leaning against the same tree for dinner, he found 7 ticks either on him or his gear. I found none on or near me. He took one of the ticks he found crawling on his equipment and put it on my pant leg (which I had tucked into my sock after he found the first tick). It walked around for a while, but stopped its progress after five minutes. At the fifteen minute point, it turned over onto it's back, taking the "dead bug" stance.
I treat my backpack because once on a conditioning/ training hike in the Ocala Nat'l Forest I put my pack down next to the trail for a break - and when I looked back at it, it had several ticks crawling on it.
I use the concentrated stuff from Tractor Supply. It does take a couple days for the smell to go away, and the smell does come back slightly when I start to sweat... but as someone else said, I'd rather deal with a slightly unpleasant smell than deal with the agony of Lyme Disease.