Servers is quite nice with 12.04 though, and that's what they are designed for.
To me, it's a different distro because it only comes with the lightweight choices. (I found it very time-consuming to strip down Ubuntu, compared to tweaking Lubuntu upward).
The only minor criticism I could have is that it's a lot of work to make a Lubuntu theme from scratch, because of the many components to theme.
LXDE has some usability issues (such as random glitches, which seems to be mostly resolved since 13.04) over XFCE or other desktop environments but I find it quite a joy to use, especially as I work on a single monitor but have multiple workspaces which I can tab through using alt+scroll, or using scroll on the wallpaper - for example I have development (sublime/chrome) on workspace 1, emails on workspace 2, testing on workspace 3 (which runs in the background and is handy to run).
LXDE seems to be the only desktop environment that doesn't lag when I have quite a few things open and going off at once, but I need to re-experiment with XFCE now 13.10 has come out to give it a proper go.