As others have said, it's good up to a point. Right now, the bugs come out pretty reliably by 4:15 in the afternoon. I'm good with the bug fan until about 7:30 or 8:00 by which time there are so many of them, nothing will do any good. I use when I'm relatively still - weeding, digging in a new plant, etc. I'm just glad I can go out, do 30 minutes of work and not have to shower off the DEET afterwards.
Remember, you have to replace the pad, so keep checking the indicator level.
And, when I know I'm going to be outside in bug-heaven for a while, I just go with the Ben's 100. I know it's DEET but the other alternative is a chance for EEE or West Nile. I was at a cookout Friday night in a town that typically tests positive for one or both of those and I took the Badger Balm (no one in the family went for that), the bug fan (worked for a bit for one kid) and the Ben's 100. It's what we ended up using.
NHWX