A proper plating job [so the plating doesn't peel off] requires very great care to start with a CLEAN surface.
Electroless nickel is a slightly different color and the phosphorous adds hardness, than the electrolytic nickel. Electroless is grey while electolytic is shiney silver color.
I use them extensively, and they work very well. Electroless nickel is nickel-the same color as electrolytic nickel plating. The cobalt kits work well, too. Cobalt is whiter than nickel.