We found the 80D not much more to buy than the 1/2 acre 40D, and it likely does provide a wider area of coverage.  It will use more electricity, but I intend to put it on a sensor, so it will run dusk to dawn.  As others reported, we found a pile of carnage after the first night....mostly mosquitoes.  Read the instructions about locating and baiting....ours is forty feet upwind of our hot tub, patio, and screened porch so the black light and scent bait draws bugs away from us, and intercepts those coming from upwind.  Far enough away from food and guests to avoid the health hazards reported, and the "zapping" is not obtrusively loud.