Technology has gotten much more sophisticated; the old days of simple direct spinning won't work anymore like they once did.
Are spinning utilities still worthwhile? I think they are, but you now have to use them as one stage in a process instead of the whole process itself.
To get useful ideas on how better to spin&grin you might want to check out what the other side is thinking about detecting dup content, aka "web spam."
Enter the following search terms in google:
"google 'duplicate content' patent"
or
"detect 'web spam'"