Installing the GA on linux host was one click and done in 30 seconds. The linux guest GA has wasted hours of my time, and no luck yet. I will probably just wipe off the VBox next week, if, by then, I don't figure out why after running the installer (subpar instructions, missing root key), the Vbox is still not detecting the installed Guest additions.
The very fact that you NEED a tutorial to make something work, is clear indication something is broke. Then, following the voodoo commands works for some, but not others.
A good OS should have the ability to put free sample XYZ Linux cd's at checkout of KMart (ala NetZero), and take over MSWindows as the dominant OS in a period of just a few years. There are obvious reasons, if you are honest and have dabbled, that this will not work at this time.