This is very difficult to answer. Different people has different sound perception. Some can train their ears to hear minute details in a song.

You'd need to have at least 256 bitrate (preferably 320, flac or wav) songs in order to appreciate the difference. Higher end earphone/headphones will certainly help.

Also remember that we have a high quality sound hardware (by Wolfsson), together with tweaked driver built into custom kernels (the voodoo sound), I can assure you the best possible sound quality in this sgs.

As for me, when I'm in a quite room, I enjoy my songs with AD900. When I'm outside where the environment is noisy, stock earphone is sufficient.