Ubuntu offered a slightly prettier installation experience.

Sure, no matter which distro you were installing you still had to provide a hostname, a domain name, some IP info (maybe), and an opinion on partitioning - there's only so many ways to ask the user these questions - but the ubuntu installer was prettier.

Around the time it was gaining popularity, almost every 'reviewer' (blogger) seemed to waste about 85% of their distro reviews talking about the installer - as though this was somehow important. The big sell of Debian, and Debian-derivatives, is that you install once, and then it's just in-place upgrades forever. The distro-hoppers, Microsoft evacuees, content-creators, etc - didn't really get that.

Anyway, once Ubuntu was installed it was much the same to operate as a Debian box. Obviously there were some surprising differences. Unity. Mir. One Cloud. Wubi. Upstart. Bazaar.