I own a few Kizer's, Real Steel's and Steel Will's. I do my own sharpening, that is where I can tell more or less if the steel is what they say it is. So far I am pretty sure that they are what they say.
As far as Real Steel I don't have any of their high end steels and they don't make many but I do have a few Kizer's in S35 and it seems that their heat treat is similar to Chris Reeves which means it's a little lower on the heat treat scale and makes it easier to sharpen and they perform very well. I have a few Italian knives from Steel Will's and are in M390 and they are great knives. I have found that M390 is the perfect balance between ease of sharpening and and endurance it has become my Grail steel. I now try and buy only M390 because it's such a pleasure to sharpen.
By the way don't discount S30 & S35 they are incredibly good metals and are more price friendly because it is used by a lot of knife companies now but they are still considered super steels.