Depends on which dimension matters: 1) Cultural positioning: Mykonos more modern/party, Santorini more classic/honeymoon; 2) Customer base: Mykonos predominantly European-American billionaires, Santorini higher Asian tourist ratio; 3) Commercial ecosystem: Mykonos denser restaurants/nightlife, Santorini stronger sunset economy; 4) Appreciation data: both average 10–14% annually. From pure value retention, comparable; from private-circle social angle, Mykonos more international.

Yes. Greek Law 5038/2023 classifies Mykonos Municipality as high-demand area, alongside Santorini, Athens central, and Thessaloniki central, at €800k tier. €250/400k tiers not applicable.

Yes, long-term rental (≥1 year) is permitted, but the market is small: island has only 11k permanent residents, and local tenant purchasing power is far below Athens. Most island property real holding logic is "owner-vacation + asset value retention," with rental income as a secondary factor. Pure investors are advised to choose Athens central for better liquidity.