Who cares depends on the fretwear and tone you want.
If you go over to www.stringitup.com there are full explanation of all the string types.
Lots of folks say "nickel wound" but its really nickel plated steel. The EB strings say pure nickel and must be, and must be something I missed (or is new). I know DR does some nickel strings, and Fender, Gibson, and a very few others. Fender and Gibson make no strings, but have them made and packaged. Darco is a maker (a large one at that... just not for themselves) as is d'Addario.