I don't own either of these but I can tell you the difference.
A silver black - also called silver dapple - (black plus silver gene) is usually silver-gray with a lighter to white mane and tail.
A silver smokey black (black plus silver plus cream gene) is darker. They are usually all one color, sometimes the mane is a bit lighter but it wont be white. They are basically......for lack of scientific adjectives.... different shades of weird brown.
Although you are adding the cream, which sounds like it would make the horse lighter, it is the darker of the to.
The reason for this is that cream inhibits the expression of silver. This means the silver wont have as much of an effect on the base color. So while silver dapples are quite their own color and far from black, the smokey silver dapple looks much closer to the black. This is also obvious with silver bays and buckskins. Take a look at a typical bay. You've got a few on your website so I wont bother posting pics. Now compare that to a silver bay....huge difference right? The body color is different and lighter and the mane is mostly white/offwhite. Same with silver and black. Now look at a regular buckskin. Compare that to a silver buckskin.....not as much as a difference between those two. So that why the dilute gene will make a silver smokey black darker.
I hope Jill sees this thread as she's got examples of everything I've mentioned here, a few silver blacks and a smokey silver black stallion.
As to preference to each their own. But personally, I love silver blacks because I tend to love to see a contrast between body color and mane/tail. However, Jill's Destiny's color is
.
Would love to see this guy, if you could pm me his pics I could say which he is.
Sorry for the essay, I get easily carried away when talking of colors!
OH!