The defining characteristic of a premium grill pan is its ridge depth. Look for ridges at least high.

High ridges provide deeper "valleys" for fat and oils to collect away from your protein, reducing overall greasiness. 2. Deep Sidewalls (High Pan Sides)

Deeper ridges create more dramatic, charred grill marks on meats and vegetables.

Standard grill pans often have low sides, but "deep" models (like those from Anolon or Farberware ) offer significant advantages: 11-Inch Deep Square Grill Pan - Anolon