I am pretty happy with it and have considered getting a second as we have about 2 acres of "cleared" area around the cabin/shop and each unit is suppose to handle 1 acre.
I have the defender, which uses household current. I also had the battery powered one and worked well until the battery crapped out and then even with new batteries, just could not get it to work.
I will say that no matter which unit you get, you do have to be diligent in your 21 day maintenance program of clearing the propane tank and units propane input. Plus you have to use their CO2 device to clear the unit of old gas and replace the attractant (octenol). So in addition to the cost of the propane every 21 days, you will have to replace the attractant (about 7 bucks) and use one CO2 cartridge (about 3 bucks).
Start it early in the season and keep it going through the season and it will really make a big difference in your mosquito population and like I said in the journal, it catches the black flies too, just not as effectively.
I would recommend it to anyone, but with the knowledge that it will take some effort on the owners part to make sure it is maintained and running properly all season, otherwise it is just a very expensive yard ornament. I have had this one for about 5 years and still works like new.
-John