If you want an inexpensive natural stone set to get you rolling, this should do the trick. The two-stone set is probably sufficient, if you've already got a Surgical Black stone.
The "hard black" stone in the three-stone set, here, is exactly the same as "surgical" black; they're also sometimes called "true black", "true hard", or "translucent", depending on colour. All of those are the same grade.
The three-stone set comes with slightly larger stones, which is a bit nicer. One of the previous purchasers mentioned the stones being not-so-flat... that would be my only concern with this buy. Probably wouldn't matter for most pocket knives, but more sensitive blades (fine kitchen knives, razors) really wouldn't appreciate it.