Granada's geography makes the neighbourhood question unavoidable. The city is built on three hills: the Alhambra on one, the Albaicín on another, Sacromonte on the third, with the flat modern city spread across the valley between them. Each hill has a distinct character, a different pace, and a completely different reason to stay there. The zones below (Centro, Realejo, Universidad, and Zaidín) follow a different logic: convenience, value, or the particular pleasure of a city that is actually functioning around you.
Most visitors default to Centro because it is closest to everything. That is a reasonable choice, but it is rarely the best one. The Albaicín is worth the climb for reasons that have nothing to do with the Mirador de San Nicolás view, though the view is real enough. The Realejo, at the foot of the Alhambra hill, is where Granada's tapas concentration is highest and the tourist-to-local ratio is still tilted in your favour. Universidad is where the city stops performing for visitors entirely.
This guide ranks the six main neighbourhoods by what they offer a first-time visitor with limited time. The criteria: walking distance from the major monuments, quality of independent restaurants and bars (Granada's free-tapas tradition means this question matters more than in most Spanish cities), atmosphere at different times of day, and whether the neighbourhood has something worth seeing that is not already in every other guide.