Copy CD

Is there a real difference at the listening between a copy (bit by bit) and an original CD ? Have you got to experience it on high-end stuff to know which one is the copy in the case of a blind test ?
I have a Philips 765 CD dual-deck CD recorder (xmas present for wife). It doesn't sound very impressive as a CD player, but I have never been able to tell the difference between a digital copy made with the machine and the original disc (I use the philips as a transport through an MSB Link DAC). I have heard other people say they can tell the difference depending on the brand of blank disc they use. It probably depends on the transparency of your system and your ears. I would listen for yourself.
My friends and I did a rather exausting comparison last year. OK, on a very revealing ($20000) system, disks copied from a hi-end Meridian transport to a ridiculously expensive professional Marantz CD-R were slightly better than the originals. This is probably due to the "pre-groove" on the blank CD-R disks that eases the load on laser tracking mechanisms. On lesser CD-R recorders the copies were very close. We could easily hear the loss of quality from the dual deck Philips, but not so from the expensive consumer Marantz or the professional Otari. Using a computer CD-R we also heard the loss of quality, especially when reading above 4x recording above 2x. This was manifested as harshness (Plextor) or mudiness (Yamaha). On the Meridian-Marantz setup we also heard differences between different CD-R pigments; the feeling was that Mitsui, Fuji and Verbatim were the best. This may depend on how well a particular laser works with a particular dye. However in my $3000 system the difference between the original and a computer-copied CD at 2x is audible only on reference quality recordings.