"Kent Road Bike" in bikes list hints towards an answer.
Originally Posted by
eric044
So, is my experience due mostly to the quality of the freewheels I've tried?
Probably so. If you consider Kent and Spalding road bikes keepers then yeah, you've been riding bikes with the crappiest imaginable freewheels, derailleurs, shifters, etc. Your single speed conversions surely made them much more enjoyable.