Xubuntu's original plan was to be a small and lightweight as possible. Over time it seems that Lubuntu has taken that over and that Xubuntu has simply become a slightly heavier version of the same thing. It is still fairly lightweight, but it isn't as lightweight as it used to be.
Xubuntu now requires users to have a DVD drive since the installer media is larger than 700 MB.
The default Xubuntu 13.04 desktop.
Like usual there are hundreds of software updates to install on first boot.
You can also see that there is a single bar at the top of the screen that now contains everything, and there is only one menu bar now (compared with previous versions).
It is also possible to spot another Linux annoyance: the clock defaults to military time. I am not serving in the military, so I don't want to see that, I want to see a normal clock in 12-hour time like the real world has things.
The about dialog reveals that Xubuntu uses XFCE 4.10.
As before there are a number of desktop backgrounds included by default. Lubuntu could learn from this.
Like all previous versions (but unlike Ubuntu), there are two virtual workspaces by default. It is possible to add more.
The single menu makes it much easier to find everything, but might involve more mouse movement than you would like.