My wife and I both suffer from severe allergies and live in a dusty desert enviornment. The Filtrete Allergen Filter has been a blessing by a huge reduction of pollen in our Central A/C system.
My cooling/heating system is checked biannually by a HVAC specialist company. They are always impressed with how clean my system is and praise me for changing my Filtrete filters as recommended. I tell them it is because of the outstanding product I use.
I have been purchasing these for a few years now and find that they do a really great job at minimizing dust and whatnot. I frequently take advantage of the available rebates to lower the cost even further than the sales that I find. During the summer I change the filter about every 6 weeks, due to the constant AC use, but max them out at 90 days for the winter months.