Apple refurbs, in general, are about as "new" as the non-refurbs.
I've had a great deal of experience with Apple products and have never seen a single refurb arrive in any less than perfect condition. If it was opened and placed on a table side-by-side with the same new product, you'd never be able to tell the difference.
In addition, I've never seen a DOA when dealing with refurbs, but have experienced this many times with new Apple product.
I think, as someone mentioned, a great many (if not a majority) of refurbished products Apple sells are flawless, unused returns that can't be resold as new. And the remaining products are totally refreshed to the point that they're indistinguishable from a new product and essentially unused.
And, of course, there's always the fact that you know a refurb has actually been inspected and QC'd extensively, rather than the less strict QC a new product goes through before it's placed in a retail box and shipped to stores. And to address what one person brought up, I've never seen a difference in resale value between a refurbished Apple product and a new Apple product on the secondary market once they're both used, so you actually make out a little in the end on resale value.
Feel as you may about the terms "refurbished" and "used," but neither of these really apply to Apple's refreshed products - they're unlike anything else in the industry.