While I like the idea they have, to show the changing chemical composition of mixes of oil blends, it's impossible to actually see how it works. The free version give you 4 oils to mix with so you can see how it works. If they had put a couple well known, or well used oils, that world make sense! However, I've only heard of one of the sample oils! They also do not list ANY information on each oil. So, although they have a common name, and Latin name (Such as "Amyris, Amyris Balsamifera"), you cannot see what exactly that oil is for, or from. So the idea of learning anything is lost.
The second problem is, to unlock all the oils, it's $20!! Since I can't actually see how it works well with the oils they have to sample, there's no way I'm going to spend $20 on the CHANCE that it will work well. Especially if I still have to flip back and forth and look up which oils are what! I'll just delete the app and stick to my books.