I probably have a 50/50 mix of EO/FO soaps, and the FOs do seem to sell a bit better. Will just depend on your target market. I've sold at a "crunchy granola" (that's the term around here, no offense ) and sold FOs 2:1, which really surprised me lol... I have more fun with the EOs though, I love mixing. Some EOs do fade quickly and need to be anchored with base notes. Another disadvantage is some of the nice ones can be spendy, though there are EOs that are prices comparatively to FOs. Soybean oil is nice and conditioning (and inexpensive!), but a very "soft oil", so I would make sure to use enough hard oils to compensate. I've also heard some people have problems with DOS (dreaded orange spots) when they use too high of a percentage of soy. Natural color work great - you won't get the very bright colors of the synthetic dyes, but clays, ultramarines and oxides (if you want to consider them nature), herbs, spices all make nice colors.