Both are beautiful, and both are easily distinguishable from natural diamonds for being too perfect. The irony is that natural diamonds increase in value if they have fewer imperfections, but almost no natural diamonds have zero imperfections.
Value-wise, in theory a natural diamond will hold its value over time, but in practice the value of natural diamonds is manipulated by the diamond conglomerates that control the market. We won’t “exhaust the supply” of diamonds in our lifetimes, so there’s not much sense in worrying about the value of the gem either way.
Are any gems “worth it”? That’s between you and your wallet. It’s an entirely superficial item, serving no practical purpose. To paraphrase a modern American philosopher, you can get married with paper rings. The ring is a symbol of your commitment, and as long as your fiancee enjoys wearing it everyday, don’t stress about what other people will think.