What are the pros and cons of buying a vintage engagement ring?

Go to an estate jeweler or antique shop and look at rings. Only buy jewelry that you can inspect in person and view under a jewelers loop. I've been engaged twice and have shelled out a grand total of $15,000 for two rings and did some heavy duty shopping before I made the purchase. Ebay is not a good source unless you have the option of returning the ring with no strings attached.