I'm a registered user of OmniOutliner and like the tool and enjoyed your article.
A couple of shortcomings future users need to be aware of, most involves it’s weak printing environment.
You cannot set page breaks.
It won’t print the column headings.
You cannot make your outline look like a table with vertical lines separating the different rows.
I’ve found if I use the tool for “screen work”, all is OK, but if I want to print the information to show to a client . . . the program becomes very wanting.