There’s some tradeoff between airflow and performance, but if you’re interested in reducing pollen, dust, pet dander, etc from your interior, a high-performance pleated filter will outperform cheap, microspun filters. The higher the MERV rating, the better the filtration. Airflow certainly enters the equation, but shouldn’t be an issue with most filters and most systems.
http://www.3m.com/us/home_leisure/filtrete/51_characteristics.jhtml