I purchased the BK-80D and I've been using this product for about a week - only when it gets dark.  It attracts ALL kinds of bugs and does leave a whole bunch of dead bugs on the floor (as stated by others).  We had been infested with mosquitos and it was getting hard enjoying the outside.  I can't tell how many actual mosquitos it zaps since they are kind of small, but i can say that we've been outside all week long and so far have not been bothered by mosquito bites anymore.  I can't say the zapper has done it all since some days have been windy and there are less insects anyway, but other nights without much wind have actually been very enjoyable and mosquito-free.  Just one week ago - before the zapper - we were actually running to get back inside with all the mosquito bites.  This week has been amazing.  I hope it continues to work.