Firs of all, keep in mind that I am very new at this. I've only been experimenting with perfumery for a few months. My opinion is that sooner or later you will want to use synthetics to help 'blur' some of the essential oils. I've found that when I use only natural components, it's very easy to smell the individual notes. There isn't the ambiguity that my favorite frags have. It could be that I'm just not experienced enough with naturals yet, but I recently started adding synthetics to my experiments, and have been very happy with the results. There is much more control because one is working with individual molecules at a time instead of possibly hundreds when you use a complex ingredient like Jasmine or Rose Absolute.
Some niche houses using only naturals are Aftelier, Joan Bassett and Profumo
I'm curious to hear what others have to say.