Harrison Jacobs/Business Insider The Greek island of Mykonos is known as a party capital and is a vacation hot spot for millionaires and billionaires. Ibiza, Spain, has a reputation as one of the top places to party in the world, with thumping 24-hour clubs, wild pool parties, and gorgeous beaches. I recently visited both and decided to compare my experiences, as many travelers choose between those islands for their vacation. While Mykonos is no doubt stunning, from its beaches to its resorts, I found it to be overpriced and overcrowded when I visited over the summer.