Bottom line: pick Istanbul for layered history, legendary street food and Bosphorus ferries; pick Dubai for sky-high architecture, desert and seamless efficiency. Istanbul is dramatically cheaper — roughly $50-90 per day for comfortable travel versus $120-200 in Dubai at a comparable standard. Sultanahmet packs the Hagia Sophia, the Blue Mosque and the Grand Bazaar into about one square kilometre of astonishing historical density; Beyoğlu's cobbled lanes, the fishermen on the Galata Bridge and the Bosphorus ferries feel unchanged in fifty years. Dubai wins on modernity and ease — the Burj Khalifa, Dubai Marina and Palm Jumeirah, all linked by an English-signed Metro, with zero acclimatisation for first-timers. The two cities are about 4-4.5 hours apart by direct flight. For Middle Eastern history and street food at unbeatable value, Istanbul is hard to beat.