Analysis of core criteria of ecotourism suggests two "ideal types" based on the level of sustainability outcomes. The minimalist emphasizes superficial learning opportunities focused on charismatic megafauna, while its sustainability objectives are site-specific and status quo-oriented. The comprehensive model adopts a holistic and global approach to attractions and interpretation that fosters environmental enhancement, deep understanding, and transformation of behavior. It is argued that the comprehensive model can best promote global sustainability by accommodating selected hard (or small-scale) and soft (or large-scale) characteristics, thereby taking advantage of the economies of scale offered by the latter.