The OEM WRX cabin filter seems akin to a coffee filter (super thin paper, one basic filtration layer, no charcoal, etc). I was amazed how even after ~2k miles on the odometer in clean/mild conditions, that my interior glass gets so foggy/filmy (non-smoker, drive with windows up, etc).
I looked at other USDM Subaru model cabin filters (Outback, etc), and they seem to use a more powerful/higher quality multilayer filter, unlike the WRX.
Time will tell how much more effective this Overtake unit is, but I figured it can't be any worse than the stock unit. Easy install, fair price. Why not?