I dislike the look of Droid Serif. I use Droid Sans as my UI font on my netbook (running Ubuntu), though. I'll certainly compare them when the Ubuntu font is released.
Note that font rendering differs massively between distributions. I prefer Ubuntu's softer (OS X -style) look best. Others might prefer Fedora's crisp (Windows-style) rendering.
If you use the operator, it's (hopefully) safe to assume you know what it does. Then you should also know what interleaving the operator between the list elements does. Which is exactly what the reduction does. I don't understand your problem with it.