THOR420 Unfortunately, X-Plane has historically had issues with documentation, but as is implied in most 'flight' simulators, you fly. I would highly recommend visiting the sites listed here: http://x-plane.com/xworld.html. They are right on the mark saying x-plane.org is "THE PLACE for newsgroups, downloads, etc". The people are extremely helpful and knowledgeable about all things X-Plane.
The user interface is what you get unless you want to change the look of it (which is not that difficult to do). I am not sure what you mean saying that it "looks like a flavor of Linux". I have used Linux since 1994ish and for some reason I think you meant to say: looks like GTK+ running on X Windows System. Most of my Linux boxes don't even have graphical user interfaces.
All in all, most serious flight simmers would agree that as far as real world flight physics accuracy goes, X-Plane is the only choice. It is too bad you thought it a disappointment.
(Version 9.0b12)