Those who say it's a gimmick as you say, have never used one.
To test if it's a gimmick or not, buy one, go out into the woods in a totally skeeter infested area and don't turn it on yet....Wait until you are covered in bites and can't open your eyes without the skeeters trying to feed on your eyelids...Now, turn on the Thermacell and you'll be a believer in this gimmick from then on.
Will it block every one of them brom biting?...Out in an open environment with a slight breeze probably not, but you may get one to buzz around a little, but turn it off like mentioned above you you'll understand the rave reviews.

Not a gimmick, they are the real deal.

Here's a similar test. Go into the east texas woods. Turn it on right away. When you get board and want to swat skeeters, turn it off. You can marvel at how fast they come.

i don't use anything. Mosqis can bite someone thats always on the move.

Well Thanks guys. I bought one. Used it last weekend.....WOW, no mosquito! It really works....

I watched one or two fly into the popup, and right back out......