Nathan’s Delta 3V is not regular 3V. Delta 3V on a knife where Nathan has optimized the cutting angle is a special beast. It has better edge stability, toughness, sharpenability, and stain resistance than a typical 3V knife. Aeb-l is very tough and has a fine grain structure that takes a razor edge. I love it and think it’s a great steel, especially at higher hardness. But Nate is known for Delta 3V and Delta 3V will outpace aeb-l.
Now, real talk: will you notice the difference? Many CPKs don’t get used to the point where the differences matter. From my perspective, since CPK is known for delta 3V, maybe it makes a lot of sense to pick up a CPK in a non Delta 3V steel. It will be cheaper and you’ll still get all the other stuff that makes CPK great: the handles, the blade angle, the fit and finish, and etc. This is purely, 100% my opinion but maybe it’s better to start on aeb-l and see if you even like the Dek. Because steel is just one element in a knife and maybe it’s not even the most important one, you know what I mean?