Which will people prefer fractions or decimals?
In general it is not. Some people find fractions easy to work with while others prefer percentages. Personally, I prefer fractions because they are precise whereas percentages can entail non-terminating decimals or truncation - either of which can introduce small errors which can build up in complicated calculations. Having said that, it is easier to compare percentages because the [implied] denominator is the same: 100.
Decimals and fractions are alike because all decimals are fractions and all fractions are decimals. As an example: 1/2, which is one-half, is the same as 0.5. The same is true for 2/4. 3/6, 4/8, and so on. Essentially all decimal are the quotient of two numbers divided by one another, which is a fraction.