One open-source application vendor with whom I met this week said it believes open source is far more than just a marketing differentiaton. While it isn't hurting this company to use the "open source" buzzword to open press and venture funding doors that might otherwise be closed to it, company officials say they believe the open-source development process has allowed the company to create a superior product.

Another operating system vendor, QNX, presented the opposite argument to me. The real-time operating system vendor says its tel. cos, medical and consumer-electronics customers would not embed its operating system if it were open source, as they don't want to make public their code customizations.

What's your take? Should all software be open-sourced? Or is there still an argument to be made for the advantages of proprietary development (besides the obvious one of making money by charging for software). Do let us know.