This article's got a lot of inaccuracies (Unix based systems all use X and a window manager? Has the guy even used OS X?) and honestly, it doesn't really even say that much about Haiku!
Just so people know, this is not a editor, but just a person who wanted to post an article. Osnews tends to have a lot of articles from people, and their quality does seem to vary a lot.<p>As you surmized the site focuses on mainly on hobby os's, its not a site based on productivity. a lot of these hobby os's once had their day in the sun (or at least the os they were modeled after, OS2, BEOS, IRIX, AMIGA) its a lot of fun to remember and even play with them, but few if any make their full time livings maintaining or using these os's.
Having tried Haiku a few weeks ago, I will say it has a lot of potential. The fact that is has a HIG (human interface guidelines) means it could actually go beyond a hobby OS. I'd like to see some more developers get behind this and see where it goes.