I found it very interesting. I have heard a few fellow shooters complaining that their filters actually degraded the image and had removed them completely. On inspection I found they were cheap non-branded filters.
I mainly have either Hoya or Sigma but I usually sell a lens with the attached filter so most of my old ones have now been replaced with newer Pro1 or HD usually bought when on special offer or bundled.
All my Sony SLT gear gone. Still got my RX100 though.