Ottopop -
I haven't used Rowaphos, but a lot of people equate more expensive = better product. While this is often the case, it's not always true. Also remember, that when you get phosban, it's by the dry weight. I believe that Rowaphos is by the wet weight. So a 100 gram of Phosban may be more than 100 gram of Rowaphos.
Richard Harker's article at least tries to do a objective testing on both products. I tend to trust his results more than someone say "Brand X is better than brand Y because...." without any empirical data to back up their statement.
Minh