There is no definitive answer to this question because it depends on what your idea of “the best” is. The primary distinctions between these weights are in terms of color and durability. Because 24K (pure) gold is soft, other base metals are alloyed or blended with it to strengthen its hardness, durability, and look.
14K, 18K and 24K gold are among the most popular selections of precious metals for jewelry. The main difference between them is the gold percentage, as you can see above. Another difference is that the jewelry made of 18K gold has a richer yellow color in contrast to those made of 14K, which has a lighter tone due to the added alloys.
However, it doesn't mean that jewelry made of 14K gold is worse than those made of 18K. In fact, they tend to be more durable and harder since they contain more alloy.