There are a few good knife steels on the market, but 52100 is probably one of the best out of carbon steels. It has fine grain, some resistance to rust, but more importantly, it responds very well to heat treatment. One can heat treat for sharpness, wear resistance, or both.
Another great thing about 52100 is it responds very well to stropping. I have sent knives to pro kitchen for testing (with my earlier HT which since improved) and the feedback I got was that a knife could go for a month or even longer between sharpening, with just stropping. How many steels could do that?
Makers like Bob Kramer, Bill Burke, Ed Fowler and countless others use 52100 extensively and some even consider it "super steel". Kind of funny, as on paper, it is just an OK steel.
I don't want to sound like I am shelling for 52100, so I will continue sending out knives for testing in pro environment and have them reviewed on the forum. This hopefully will settle the claim.