This has been working for me for many months in our apartment. I had two, but dropped one on the floor and the blade broke, so I'm ordering another. I had reviewed this a while back, but it is on an Amazon page for another seller, which no longer sells it, so it doesn't appear when you search.
Anyway, perhaps the mosquitos are dumber here in DC than eleswhere, but eventually they end up in or around the trap, dead. Most of the mosquitos actually don't die in the trap's net basket, but are battered by the fan blade and end up laying in front of or behind the traps (they get knocked out through vents in the back, I think). So if at first you don't not think it's working, put the trap on white sheet of paper and you'll find them.
We keep them running at night, when the mosquitos are actively looking for us, and perhaps that's when the traps work best -- in the dark with those enticing blue led lights.