The customer can and will perceive bugs. E.g., I used to own an MP3 player that would crash regularly. Everybody can notice that a crashing MP3 player is lackin

The customer can and will perceive bugs. E.g., I used to own an MP3 player that would crash regularly. Everybody can notice that a crashing MP3 player is lacking in quality. What is more difficult is knowing who in the team contributed to a good or to a bad result and who of the programmers was a dead weight on the team. One really needs to know a lot about programming to say anything useful about that. I agree that what the user can tell is the most important attribute of quality. There is is another important matter, though. This is how easy it is to modify the software. Good code can relatively easily be extended to incorporate new features and bad code makes this as difficult as possible.