This depends on your own preferences because they’re both amazing cuts. A round diamond is a true circular shape while oval-cut diamonds are elongated with rounded edges. Both cuts are durable shapes with plenty of brilliance. If you’d like another type of gemstone as a center stone, consider moissanite, sapphire, or emeralds. While some like the look of opal, they’re better as an accent rather than a center stone because of durability.