What is it all about? This is just simple tool for mounting pendrives and alikes when inserted -- something like ivman or functionality integrated in KDE/GNOME.
So what's the difference? Unlike those tools uam doesn't use HAL. Unlike traditional automounters it doesn't require you to sacrifice memory for three additional daemons -- HAL, dbus & the mounter itself. Instead you just have to have udev running (which you'd like to have anyway) and uam will be called by it everytime an USB stick is inserted.