What's the best iOS app for building and managing a virtual city with ongoing challenges?

SimCity BuildIt is a comprehensive city-building simulation that allows players to design, expand, and manage a detailed metropolis from scratch. The app excels in providing a balanced mix of creative freedom and strategic depth, with features like zoning for residential, commercial, and industrial areas, managing essential services such as power and water, and optimizing transportation to reduce traffic jams. Players can engage in production chains, crafting goods and trading with other cities to accumulate resources and currency. Regular challenges, including seasonal events and disaster scenarios, introduce dynamic goals that encourage daily participation and problem-solving. For instance, during a monster attack event, users must fortify their city's defenses, adding a layer of excitement to routine management. However, some reviews highlight occasional server connectivity issues that can disrupt gameplay, and a few players find specific mechanics, like the train system and bolt production, overly complex or reliant on chance. Despite these minor drawbacks, the app's extensive content, social features like club collaborations, and frequent updates make it a reliable choice for those seeking an immersive simulation experience. It's well-suited for quick sessions during downtime or more involved planning on weekends, catering to a wide range of play styles.