My high-level impression (based on a small amount of experience) is that if you want to ship a modified distro, it's easier to base your work on Debian than to

My high-level impression (based on a small amount of experience) is that if you want to ship a modified distro, it's easier to base your work on Debian than to based it on Ubuntu. The Debian project puts a lot of effort into making a wide variety of configurations work well. Ubuntu focuses on a single configuration, more or less, and they don't seem to mind if that introduces bugs in other configurations. I personally switched from Ubuntu back to Debian when I realized that I was dealing with Ubuntu-specific bugs more often than I was benefiting from Ubuntu-specific features.