IMHO, the personal statement is probably "worth" more than secondaries assuming that you have written a good personal statement. Interviews come after secondaries because well, its mostly about the $$ they collect from secondaries. As for secondaries carrying you on (for those with essays), I believe to conjecture which one is more important to garner an interview is a moot point because one really cannot function solo without the other. In my opinion, I tend to believe that personal statements carry you alot further because there are many schools out there which don't have secondary essays, or give out secondaries (such as UNC) as an interview invite. For schools with secondary essays, you could have an average PS with a good secondary and vice versa and be able to get an interview. If one is glaringly bad, I imagine that it will hurt your chances in total. IMHO, I see secondaries more as a supplement to the solid foundation your AMCAS brings, but to make this as broad generalization is probably an unfair one.