I have (had) fairly severe cat allergies and a cat. I found there was a very noticeable difference between the cheap filters and the 1700 Filtrete filters. Now that I've been doing allergy immunotherapy (allergy shots) my allergies are pretty much gone, but I still stick with the better Filtrete filters based on the previous experience of how much better they are. BTW, I highly recommend seeing an allergist about immunotherapy for anyone with severe allergies, it works really well for me, and they say for 90%+ of people.