As posted, my original question was poorly worded, and I apologize to all for for my lack of clarity.
Obviously, filter quality does matter. Nobody wants crap filters.
But how much filter quality matters - from the practical standpoint of whether or not it is visible on my negatives - is less clear.
Considering that I am using moderately good lenses from Pentax and Konica, but not the really high-end stuff from Leica, or whoever - and considering I'm using faster films, hand held - and considering I am not making giant enlargements - what I was really wondering is, how good is good enough? My question should have been worded something more like, "Is there enough difference in image quality when comparing filters from such brands such as Canon, Minolta, Vivitar, Toshiba, Hoya, etc. to notice, when looking at moderate enlargements of real-world negatives?"
I now realize this question is probably impossible to answer because there is so much uncertainty about who actually made many of the filters offered by these brands over the years. Furthermore, some brands offered filters at different price points, but the technical differences which might affect image quality are not always clear from the marketing hype. In the linked test (from 2009) Hoya filters were ranked the top three, but also #14 out of 16. What I still don't know is if I would be able to see the difference between #1 and #14 on my negatives made with my gear? Based on my brief initial evaluation, my Toshiba filter seems to be good enough - for me - for now.
Thanks to all who replied! But, I am over it, and now I need to go process a couple of rolls of film.