Aus 8 A is the japanese name for 440 B, they are equal except for a little silicon percentage more in the japanese steel and performance is virtually equal. Carbon content is 0,75 so is a "high carbon steel"( from 0,50 to 0,75 is considered "medium carbon steel", from 0,75 to 1% is considered "high carbon steel", from 1% to 1,5 is considered "very high carbon steel" and beyond " ultra high carbon steel"). I don't see any problem with 8A since is a good steel highly rust resistent and hold a good edge with proper temper.
Sort of right and sort of wrong.
AUS8 (8A) is not the name for 440B in Japan. They are factually two different types of steel, there is a difference between same and similar. They are very close though in all aspects. AUS8 however has a scientifically better edge simply due to the steels smaller grain structure and composition, but really... really similar as you said. The argument of difference is like in the argument of sharpening, opinion, some feel there is, some dont. Now, I have some of each, some 440B perform on par with AUS8, and well... some 440B performs like filth compared to the same AUS8, just due to a different make and different treatment.
440 steels, AUS8, etc get a bad wrap as they are cheaper steels, and companies with crappy rep and bad heat treating give these steels a bad name.
Factually, they are really great steels for many enthusiast applications, as well as real world cuttlery applications. Heat treating has a remarkable impact on the grades of steel, hence why two makers using the same steel and even making the same blade design can often be of noticable difference in quality and efficiency.
Of course, if you talk to someone used to exotic steels sure, AUS8 sounds run of the mill cos alot of people use it, some people like to be different and have different steels even though they would have no clue as to the practical differences, and MOST enthusiasts into knives have a poor understanding of the metalurgy behind their knives (take some time to study the stuff and you soon realise very few people have an appreciation for what really goes on between the steel types).
There is a time and place for each steel, and that time and a place is also dependant on your use of the steel.
AUS6,8,10 and 440A,B,C are not the same things, but are comparable to the near same. Good steels when produced by companies who know what they are doing.
Compared to some of the cobolt steels, or infi, then sure... AUS8 looks like a joke. But the same can be said about one guy driving a highly tuned sports car compared to a run of the mill vehicle.
This is also why it pays to check where you buy these things from. I have an utmost regard for seki AUS8, I have yet to find a maker from that area that cops a bad wrap in their AUS8. I have seen AUS8 reproduced in other nations to a failing extent.