Short answer: It depends on what you want.

Quick comparison (high-level):

• City Walk — curated, stylish outdoor/streetscape dining with many trendy cafés, mid‑to‑upscale independent restaurants and international casual brands; great for al‑fresco meals, people‑watching and neighbourhood-style dining. (citywalk.ae)
• The Dubai Mall — far larger and more varied: dozens (hundreds, including food courts) of outlets spanning inexpensive fast-casual to high-end and celebrity chef restaurants, plus experiential dining and views (Dubai Fountain/Burj Khalifa area). Best if you want maximum variety or fine dining choices. (thedubaimall.com)
• Mall of the Emirates (and other big malls) — another large selection with good mid‑to‑upscale options, hotel restaurants and themed dining (Ski Dubai area, Fashion Dome, etc.); sits between City Walk’s curated vibe and Dubai Mall’s sheer scale. (en.Wikipedia.org)

Which is “better” for you:

• Pick City Walk if you want a stylish, walkable outdoors atmosphere, boutique restaurants and trendy cafés (good for date nights, relaxed brunches, Instagram‑friendly spots). (citywalk.ae)
• Pick Dubai Mall if you want the largest selection, wide price range, family food courts, and options for fine dining or specific international cuisines — also convenient if you plan to visit Burj Khalifa, Dubai Aquarium, or want one-stop variety. (thedubaimall.com)
• Pick Mall of the Emirates if you want good restaurants plus attractions like Ski Dubai and hotel dining options. (en.Wikipedia.org)

If you tell me the kind of meal you’re after (budget, cuisine, ambience — e.g., casual burger, fine dining, al‑fresco brunch, family friendly), I can recommend specific restaurants at City Walk or the other malls and show menus/reservations.