I would agree with Michael, that the sundance II is my favorite. I have tryed the plastic entrance traps without sucess, to flimsey and confusing for the bees when placed on a mature hive.
I have started placing the traps only on new splits, and this appears to work best. Everyone is new to the entrance and things ramp up slowly such that there are no troubles in adapting to the existance of the trap. Of late I only place a pollen trap on a mature hive in febuary, no confusion and the girls fall right in line.
I have no criticism of the people who trap on an intermitent basis, however, my traps go on the first week in Febuary and come off the first week in November. North Carloina is a well watered, long growing season region of the country. As such, each hive will produce about 50 pounds of trapped pollen a year. We are now into July and the collections are down, but the girls are still bringing in about 3 oz a day per hive. There are a number of research articles and well documented books detailing the adjustments bees make to ensure adequate hive pollen stores. I have no issues with hive brood rearing.
Pollen sells for abour 15 dollars a pound on the internet.