Sgt_Kickaxe - 6:55 am on Aug 22, 2010 (gmt 0)
301 redirects are also webmaster input...
Indeed, but when a webmaster places it on a page that page is removed from search. Google will oblige removing pages but take our word on the page receiving the 301 benefit? nah.
In terms of effect, when compared with canonical issues, 301 kills the dupe page entirely. Rel="canonical" is still hit and miss.