If you haven't caught it yet, Ann Turner has a terrific article (title above) on her experience with full sequence mtDNA testing in the Fall 2007 issue of New England Ancestors (pages 49-51). If you're not a NEHGS member, do whatever you have to to get a copy!
And based on the recent chit-chat on the lists, she's not the only one to have found a meaningful match already. Looks as if mtDNA is starting to come into its own!