Over the years I've been happy with refurb lenses and even a refurb body (5 series with about 3000 shutter actuations). But, even though their technology is great and even though the Canon has prospered, they really ought to spend some time with their website accuracy and inventory control. Ordered a lens on August 5 ("in stock" both on the day I ordered and even showing "in stock" the next day) but has been "processing" since. One never knows exactly if and when it will ship.
Refurbs are, in some ways, better than new because they have been inspected by Canon before the sale and they come with the same warranty as new. But, I will not sell the old lens I am replacing until the one on order actually ships!