Used this hiking / camping toward the end of summer for three days and nights outdoors. Never got bit once. So I think it must work. Did not notice any horrible smell or after effect - in fact it was really easy to use. Spray and forget about it.
I had high hopes for this product in the backcountry since I have used Bens insect repellent at picnics before with sucssess. I was disappointed with its performance, especially with black flies. It did not seem to repel or even keep them from landing on my skin! I did not have any other insect repellent with me and it made for a less than stellar weekend backpacking. Luckily, the black flies had JUST starting biting...