I have one that I've used. Generally, I prefer the bottom mounted traps as they don't need emptying as often and the pollen will mostly stay dry if it rains. The plastic front mounted trap needs to be emptied about every day. Also, it if rains the pollen becomes a soggy mess. There is less area for the bees to go through than in a bottom mounted trap, so the bees seem to get backed up at the entrance when there is a good flow going on. With that said, the one I have does collect pollen in appreciable amounts. They also work good if you happen to be using a top bar hive. And the price is pretty decent.