This was the first steel I recall carrying the label of "super steel". 440C had been the old standard of stainless steels for custom makers around here. Not well known until used by a certain well known knifemaker. It caught on fast and helped a whole generation realize the best knives didn't have to come from forging. Stock removal could make excellent knives that could keep up with the best from the forging crowds, which caused them to begin pushing the envelope as well, leading to better knives through better control of the whole process, cryo, etc..
154cm is, or acts like a stainless high speed steel with a high and low temper. It's a clean steel well ahead of 440A, and C when done well. Of course BG42 ( stainless M50 HS bearing steel) took it even further with clean steel, and better wear resistance along with higher attainable hardness levels.
We sure have come a long way since then. Now there are people proclaiming new "super steels" every other day usually on steels that are only new to them, or repackages of already existing steels.
And, yes. I still like 154cm, and better yet CPM 154. I also like 14-4or whatever Latrobe called their version. ATS 34, and RWL 34 have found their markets as well. To be honest I owned an ATS 34 bladed knife before an actual 154cm knife as when I finally had the money to buy the more expensive knives ATS 34 had made some inroads into the cutlery world.