Adding the HC (High Carbon) to 420 steel is relatively recent, at least in the popular knife world. The steel that everyone automatically thinks of when they hear 420 is 420J2 -- also known as "butter steel," and similar things. A very high percentage of the real POS knives of the world have 420J2 steel for the blade. It has low carbon content, so can't be made very hard, therefore can't hold an edge much more than a couple minutes, some think.
I read somewhere that Darrel Ralph was very concerned about the thought of using 420 steel for the EDC. He was apparently given a demonstration of 420HC, and was satisfied that it was an adequate steel to use for his collaboration knife.
Even with the added carbon, 420HC is not likely to hold an edge as well as 154Cm steel. Whether or not it takes as good an edge may be fairly subjective. It very well might do a bit better in the stainless department than 154CM, but the differences are not likely to be striking, I don't think.
I got the ArcLite in the 420HC steel -- that is all that was available. It has resisted my corrosive body sweat pretty well, this far. I think you'll be okay with it on your EDC. I'd just be sure to check your edge fairly frequently, to make sure it is as sharp as you need it. The big worry in a steel not known for holding an edge is that it may get used for utility purposes, and then if a self defense situation forces you to rely on the knife, that the blade won't be sharp enough to do what you need it to do..
The easiest solution to that is to carry 2 or more knives. I carry around 4 most of the time, but then again, I'm a certified paranoiac. You probably aren't. To me, though, it only makes sense to have a "fall back" blade somewhere on you, whatever it is.