What sorts of oils and butters are best for your hair?
Depending upon where it is grown and the environmental conditions of that year, as well as soil quality, shea butter can vary significantly in its ratio of stearic acid to oleic acid. This will affect its melting point, and thus, its softness. If there is a lot more oleic acid relative to stearic acid in a particular batch, it will be a much softer and oily product, and will behave somewhat differently on the hair. Processing (methods of extraction, filtering, use of heat, hydrogenation) can also drastically affect the unsaturated oil composition, so if purchasing shea butter itself, carefully read the label so you are aware of the quality of butter you are getting. A pure shea butter contains no emulsifiers or perfumes, but is purely the mixture of fatty acids that were extracted from the fruit.
Incorporation of shea butter into a conditioning product involves melting it and dissolving it into an emulsifier and then mixing that into the product. Although the butter is melted and mixed into a liquid, its mixture of fatty acids should remain intact (unless high heat was used, which is not typical). Therefore, it is still the same "butter", simply because the term butter is not actually very meaningful. The inherent molecular structure is unchanged.
It is also interesting to note that while coconut oil is comprised almost entirely of saturated fatty acids, it is still referred to as an oil, rather than a butter. This is due to the lower molecular weight of the major fatty acids in coconut oil, which give it a lower melting point; typically right around room temperature. This is another clue that the terms butter and oil are not always very precise or meaningful. For this reason, it is a good idea to look at the fatty acid content of a particular butter or oil you would like to try and to understand what sort of performance you might expect based upon its chemistry, rather than what it is called.