I attended a seminar presented by Barry Crown, and only had the opportunity to demo RODEL. I can only advise you to be aware that the three are based on different variables. RODEL and Arcady are based on UK empirical data, whereas aaSidra is based on gap theory. The two theories can produce vastly different results. Obviously, the proponents of each software will tell you that their theory is correct. I would encourage you to research the differences between the theories and decide for yourself which is appropriate before diving into a particular piece of software.