Steel, heat treat, and geometry. It always comes down to those three things.
If you adjust your sharpening to those things, you can get any steel sharp (unless it's pot metal or something). We all have favorites to sharpen due to our own methods of sharpening. When I hand sharpen, I can get some knives sharp in no time, and some take me forever. Generally the harder and higher carbide content steels (especially CPM) get sharp much faster than others, at least the way that I sharpen.
But when I put any knife on my Edge Pro, I can get any steel just as sharp as any other steel.