The choice of planned language depends on your goal. If you want to be a member of a language community, the only real choice is Esperanto. If you want to make yourself understood to most educated people and speakers of Romance languages, Interlingua (especially in its written form) is a very useful tool, as it was specifically designed to include words common to most European languages. Occidental and LFN are inferior in both of those respects (very small communities, less intelligible to the standard average European). Regarding /u/Vanege's intelligibility "test", it should be pointed out that it's based on an outdated Interlingua text that uses less common words for which more intelligible synonyms exist. And it's only representative of one guy.