The MacBook Air M4 edges ahead overall with 18+ hour battery life per Notebookcheck tests and silent fanless operation versus the XPS 15's 10-12 hours. Dell XPS 15 provides a superior 15.6-inch 120Hz OLED display and more ports but at the cost of added weight and shorter endurance. MacBook Air M4 is the stronger pick for most users unless a large Windows display is required.