Real Environment X - it enhances weather, clouds, water, lighting..basically all of the environmental aspects of the sim
GEX enhances the ground textures and some night lighting, especially the lighting from the windows of buildings
FSWaterConfig allows you to increase the surface reflection, surface wave animations, and tint of the water - it lets you customize the appearance of the Sun and Moon
light on the water especially
These three programs work together seamlessly and allow you to personalize the way the FSX world looks, to suit your taste
and Shade does what it does to complete the package - if you compare default FSX to FSX enhanced by these four programs you will see
that there IS no comparison