This is my bug repellant of choice. I'm just not a fan of DEET, because as effective as it can be, I don't like all the warning labels, melted plastics, eroded synthetic clothing, and skin-burning sensations that can accompany it.
I used this in the Eastern Sierra last year, which was a banner year for mosquitoes (think thick black clouds), and had great results. I also like the small size of these and of the one ounce spray bottle, it doesn't take up much room or weigh a lot in my pack. These are good for applying to areas where you want to be precise, or if you prefer the wipes to a spray.
If you are giving any thought to getting off of the DEET train, give this stuff a shot.
The only reason I picked these up was to be able to protect my face and ears from the bug onslaught that I would no doubt face when I visited Guatemala. I've always hated showering my face with bug spray's and these seemed like a great way to avoid having to taste bug spray on my lips all day long. As for how effective they are, I can't give you a rating. All I can say is that my face never got bit and my lips tasted fresh all day long. Didn't seem to have issues with sweat washing away the protection either.
I'd drink DEET if it would keep the bugs away but my wife is into natural remedies so she got me some of this stuff. I don't know about the 12 hour thing but this stuff did what it was supposed to and kept the bugs off me while setting up camp, cooking and so on. It didn't have the strong DEET chemical smell either.
This stuff works... Amazingly! Was backpacking in the High Uintahs and set up camp in a moist meadow. Everyone, but me, was being mobbed by bugs. These wipes seemed to put a bug force field around my body. Best part about them; they aren't greasy at all. Will buy in the future and would recommend them to anyone.