I am thinking of buying a NutriBullet but would use it only for fruit smoothies (no spinach leaves, no sweet potatoes) so don't really know 1) if it would do anything a blender can't do. 2) Is the smallest one, 600-watts, strong enough to chomp up anything I might put in it? 3) I guess my basic question is, if I have a blender and a Cuisinart, why would I need a NutribBullet? Convince me. 4 ) If a selling point of the NutriBullet is that it preserves fiber, isn't the "solid" quality of the fiber broken down and lost when the material is NutriBullet-ized?