As already said, depends completly on the steel, heat treat and grind.
For example, D2 is a carbon steel and 12c27 is a stainless steel.
And if they are Heat treated the way they are most commonly heat treated, D2 is harder to sharpen.
maybe even 01 is harder than 12c27 (depending again on Ht)
01 has roughly 1% carbon and 12c27 has about 0.4%.
But 12c27 has alot more chromium which adds a bit to the difficulty to sharpen. but so does the little wolfrum (or tungsten) in 01.
Wheras D2's combination of 1.5% ish of carbon and its high chromium content combined make it a little harder than both to sharpen.
But i dont think there is a huge difference.
As you can see it is not a simple answer to the question. A bit like asking who is better french or english, and of course the intelligent answer is that it depends on the individual.
It was a good question! sorry i went on a bit