Here are links to a couple of web pages on the Sawyer web site:
Some very good info.
I've used DEET and Permethrin for years. Heck, I think we used almost 100% strength DEET in the jungle in my old light infantry days. The military is still issuing Permethrin clothing treatment kits to those deploying to SW Asia. I've soaked my bed netting, hammocks, etc, in Permethrin for years with no side effects either. If you're worried about putting chemicals on your skin, clothing, sleeping area, etc, look at it this way; is it better or worse than getting a vector transmitted disease such as Lyme's Disease, West Nile Virus, Yellow Fever, Malaria, etc? The chemicals probably won't affect you, but these diseases certainly could. One has to do a risk/benefit analysis, it all depends on where you're traveling too.