What I feel may make some with an attachment to a paricular steel want to debate it but in truth I doubt you'd be able to tell in use an AUS6 blade from AUS8 steel and for that matter it seems likely to me that you'd be hard pressed to tell it from the 440C, 420HC, or 154CM blades out there in the hands of users. I own several knives each in these various steels with various blade shapes and similar edge profiles and I would have to say that one blade does not really hold an edge or need touch ups any less frequently than the other based on what I've experienced in my own uses everyday. I used to be more 'snobbish' about the steels I used but once I started testing and evaluating them more I woke up to a new way of seeing things I guess.
This does not mean there are not slight performance advantages or toughness advantages from one to the other. Just that to the average user these difference would be very difficult to see I think. Perhaps in a very specific test geared toward closely following the results of each steel where you compared their performance in various mediums one could note differences and maybe even some marked differences that made one stand out as a bit better than the other but to the average end line user I doubt there would be any way they'd know which was which in a blind test with blades of all steels and none marked to tell you which was which.
They are all more than adequate steels for everyday carry beater upper folders. I might also point out that steels can vary at times from batch to batch. I've had blades in all the above steels that were for lack of a better description, crappy performers. I've owned for examaple two of the same model folder made in the same year at different times using the same steel and yet one markedly outperformed the other and noticeably took a better edge to begin with even though both were sharpened to the same angle on the Edge Pro and both were done using the same stones and hones. This could also be heat treat related and one blade may not have been properly done or somehow was not as hard as the other. We've all seen things like this so the only way to really judge steel is to use more than one and more than two of the same steels over time to get a good idea of what it can or can't do.
So, when one is bad I think it can indeed stand out at that time, but you can't judge the entire industry stockpile of that steel by your one bad blade. However consistancy is good these days and most are on par with each other but we are afterall just human and we can make some mistakes.
I've got some AUS6 blades that I find quite good at keeping up with anything else I have available to me in my safe to pull out on any given day. One of these is a great little folder that was inexpensive and yet somehow keeps up with all the so called big boys and in many ways out shines them. Go figure. In general AUS6 is tougher than all the above mentioned steels by the way. Its a good mix of great toughness, corrosion resistance and good edge keeping in a nice Japanese quality stainless steel.
STR