The advantages being that >50% of the help documentation (and forum posts) cover some derivative of Ubuntu. You also have the added benefit of installing software through PPA's which are essentially mini-repositories that 3rd parties maintain (i.e. back in Ubuntu 10.04 VLC was stuck on an older version that would not play 10-bit MKV files properly, so I simply installed their beta-channel PPA and everything worked perfectly).

I also know of several colleagues that use and enjoy Ubuntu (because Unity notwithstanding, the distribution is pretty solid) with an alternative environment like xmonad.

My experience with Debian is limited to servers, but I'd imagine a lot of the creature comforts of Ubuntu are missing on Debian when used as a personal OS.

Ubuntu is less strict on the non-free thing. Either way it doesn't really matter since you can use PPAs from ubuntu on debian and vice versa. Obviously the same goes for .deb

I think ubuntu LTS gets packages from wheezy and normal ubuntu from sid.

Debian takes the super stable approach, which means packages aren't always at the latest version. Ubuntu favours more frequent updates.

I like Debian for servers but I'd probably go with Ubuntu or Mint for desktops if I ran a linux desktop.

Debian unstable seems to be about at the same place as Ubuntu. I use it to get a minimal system, where 95% of the support forums answers for ubuntu is still valid.

Packages are upgraded more often, I think.

It's supported by a company called Canonical, but I'm not sure it adds value.

The community is larger and you may find online resources more easily.

I love the idea of Ubuntu (not that it hasn't happened many times before) and have a great deal of respect for Mark Shuttleworth for basically funding Canonical out of his own pocket. However he (and Canonical as a company) make some terrible design decisions (Unity, premature adoption of Pulse audio, and -most recently- Ubuntu going solo with display managers).

I wouldn't be the slightest bit surprised if Shuttleworth sees himself as the "Steve Jobs" of Linux and with the direction they're taking, I think Ubuntu will be like Android/Linux (ie still "Linux", but largely incompatible with the traditional desktop Linux ecosystem).

Hopefully I'm wrong. But Shuttleworth has done little to give me confidence.

Ubuntu is at least interesting because of they're efforts in patching kernel and other stuff to work with hardware properly.