We have a mosquito magnet and it works very well. Ours is the one that covers 1/2 acre, my in-laws had it and moved up to the 1 acre version. You hook it up to a propane tank and add attractant to the bottom, and it sucks them up when they get close. It catches the evil little bloodsuckers in a basket, and you drown them, then empty the basket and replace it. We have had the most success using it at the beginning of mosquito season, to get them before they start breeding. Last year we hardly had any mosquitoes. Black flies are not affected though. We also got a bug zapper at a yard sale and love to watch it zap them. (If you set it up after the bugs get bad, you have to wait a few weeks for the population to drop.) We tried the Off, personal repellant (looks like a little blue fan that you can clip on yourself, or put nearby.) It worked okay for our picnic yesterday--but we have to buy more refills to try it out in the woods, the real test!
Good luck. Oh, if you get one at a yard sale, or used, the company changed hands 2 or 3 years ago, and they weren't warrantying the old products. So if you get it cheap and it works, like we did, yeah! If you want a guarantee, then get a new one. Linda