Even though he’s talking just about the development of his iPhone application, Buzz Andersen hits the nail on the head about why quality matters for the long-term success of any software product:
One of the hardest things about shipping Birdfeed was staying committed to slaving away on such minutae while other, often less polished, clients beat me to market.
While such attention to detail may not be appreciated in the specific case, however, I’ve found that in aggregate it leads to an overall impression of quality that attracts the kind of fanatically devoted users who form the backbone of a growing, long term user base.
Attention to detail is the only way to develop high quality software, and high quality software is what leads to users so happy to use your product, it sells itself by word-of-mouth.