There is also the more High-End CD-Rs when only the best is good enough, if you are backing up your own discs and verifies each step bit for bit, it's still not as good pressed and lets not forget all pressed discs are not equally made, a really good burn is better then the cheapest backalley pressed ones.
And a note, biwax is used on cds, pressed and cd-r as when in production it's made by machines and it's going fast, it's there as a layer to see through that the discs don't stick together and can be separated.
Before a disc is copied that should be removed, washed gently in soap and hot water or by ultrasonic cleaning, actually a cd-r chould have this done before burned too but you might make more marks in the surface then the biwax distorted the surface.....
Pressed discs have a more scratch resistant acrylic layer, even cloth makes small marks on CDRs if you look at it under a microscope.
So a test take out a new disc in a cake, it looks clean as a whistle, now breath on it like you were about to clean it, weird marks and spots and whole areas becomes different looking, it's not as clean as it looks.....
Here's some real goodies when it comes to Gold CD-Rs
http://www.kmgdigitalinc.com/premium/gold-preservation-discs Kodak
http://www.mofi.com/product_p/udgcdr1.htm Ultradisc
http://www.mediasupply.com/mamgold.html Various
There has been a very good expensive one, I think it's was made by Kodak and it was at 40$ each,
a disc Deutch Grammophon used for final storage of some of their works in vaults, but seem unable to find it now.
The cheaper CD-Rs degrade in the dye in time while these have very low degradation rate, nearly non existent.
The absolute best is High Quality pressed Gold 24Karat CDs but they are very unusual, I only have one.