That depends on what you want to achieve. WED is easier for simple maps that have retangular or square scenery's (like a maze like map, or your typical Doom like shooter with lots of corridors maps). More complicated map scenery's with lots of detail can be made in a model editor. Or maybe you want to create an outdoor map, say a desert. You can use the MED (gamestudio's model editor) to easily create a 'terrain' model (.hmp if I remember correctly) for the desert. If you define better as what has more possibilities and what can reach more detail, I would say a model editor. But, why use one when you can make use of both? They both have advantages and disadvantages. Hope that kind of cleares it up .