Like probably everyone here I have heard all the anecdotal information about different filaments and how one is better at so and so than the other. What really interests me is people actually testing filaments and not just going by marketing hype.
Three youtube channels that I like for this are CNC Kitchen, Zack Freedman, and especially My Tech Fun. There are others of course.
The general feel I get from this is that PLA is the strongest, ABS/ASA is the best at heat resistance, and TPU is the flex king. Everything else is just slight variations on a theme.
What I mean is that when actually put to the test, PETG is no stronger than PLA, and might be a couple of degrees more temperature resistant but not enough to make a difference and carbon fiber filaments are actually weaker than PLA (see Clough42’s tests).
In my own personal use tests I have noticed that the “same” material from different manufacturers can be wildly different and even different colors of the same material from the same manufacturer can be different. This has caused me to do things like print a production part I needed black in gray filament, then sand and paint it black. Wild, but it works and solves a problem.
So I have pretty much settled on four basic filaments for the majority of my printing; PLA/PLA Pro+ from Hatchbox for some production and all of my test prints (almost all test prints are done in Hatchbox blue PLA), Polymaker Polymax PLA for any production pieces that don’t need serious temperature/UV resistance, Polymaker ASA for anything that needs temperature/UV resistance, and Polymaker TPU for the flexy bits.
In the past six years or so, these are the filaments I have found to be worth using and provide consistently good products. What are yours and why?