Updated: May 23, 2009
If you're even moderately serious about writing documents, LaTeX is the way to do it. Not only will your productivity increase, your documents will look professional and print-ready, with the exceptional quality of Computer Modern fonts that are simply impossible to beat.
Unfortunately, working with LaTeX is not an easy task for most people. One, it requires working without seeing the output, a concept that quite a few people can't really grasp. Two, it requires a mind-set of separating content from style, similar to HTML and CSS, whereas most people are used to working with word processors that focus on exactly the opposite. Three, just like HTML, LaTeX has elements and tags and whatnot and mastering them is practically learning a whole new "text" language.
For this reason, LaTeX frontends were built, GUI programs that help LaTeX users work visually, without getting lost in the maze of command-line text instructions. Best of all, they can see the output of their work.
LyX is my favorite LaTeX processor. It works well in both Linux and Windows, it's powerful, intuitive and simple.
If you're not happy with LyX, looking for an alternative or would like to try a pure KDE-based frontend, you should check Kile.
As said, Kile is a LaTeX editor for systems running KDE desktop. This means it is not available for Windows, yet. Installing Kile is a simple affair: most distros have it included in the repositories. Dependencies will be solved automatically, a hefty 300MB of them.
Kile is slightly overwhelming to new users, with the classic KDE detail working against them. The simplest way to begin is by creating a new document and choosing one of the templates. If you've never worked with LaTeX, you should not choose Empty Document.
Kile is similar to HTML editors, like Nvu or Bluefish. It shows the code to the user, which works both ways: it's useful to advanced LaTeX writers and can teach the newbies the basics of text processing. On the other hand, it adds clutter to the screen.
Creating formatted documents with Kile takes a bit of an effort. You will first have to build and compile the LaTeX file before being able to process it, say to PDF. You have the Log and Messages pane underneath the document windows to tell you about your progress.
Once you get to Done!, you can create final documents, with their superb good looks. For example, our document, the way it looks in Okular:
Well, both take approximately the same space on the disk (approx. 300MB). Kile is easier to install; marking a single package will solve all the missing dependencies. LyX requires additional packages to be installed manually. On the other hand, LyX runs on Windows, too.
Kile looks better, with a sharp modern look. However, the unavoidable KDE clutter can frighten new users. The more spartan LyX looks work in its favor, as it feels easier to master. While both offer similar functionality, getting around LyX is simpler and faster.
LyX also hides the code from the user, sparing him the details of text processing. Creating documents with LyX is also easier. A single click is needed, whereas Kile requires build and compilation first.
Overall, I think LyX is a more mature product, especially since it can be also used on Windows and is easier to use.
Working with Kile is a pleasure. It's not the simplest application, but it is powerful, flexible and useful. It is also well made, good looking and stable. It's a bit more difficult than LyX to master, but nothing critical.
Alas, there is no Windows version, which is a shame. Hopefully, that will change. Enjoy your new toy. Writing impressive documents is the goal of every writer and now, you have one more reason to be successful about it - and have fun along the way.