Tiger maple and curly maple are actually the same, just called by different names. The correct term for the grain configuration is "fiddleback"....don't ask me why.....but that's what it is. Some think it's formed by compression in the tree as it sways in the wind.
The tighter (closer together) the grain the more desirable. Fiddleback is found in oak, hickory, and other hard woods as well....
Tom I.