Picture #1 is tilted downwards right to left. An easy fix. Try to lower the horizon as you have it going right through the middle of the photograph. Would make for a much stronger presentation of sky vs reflection in the water. I prefer picture 3 over #2 as that foreground shrub on the right just seems to over power everything else, rather then working with the other elements, while the water runs right through the foreground. Just seems unbalanced to me. Picture 3 has a stronger foreground that the brighter lighting helps. Picture 4 is ok, just doesn't do much for me. And finally Picture 5, the best as most everyone agrees on. Stronger composition with the foreground trees nicely framing the scene. The variation in color intensity from the atmosphere over the valley really helps make this picture a success. Well done.
There are exposure issues. As an example, picture 1, the ground is basically all in heavy shadows. These are difficult scenes to exposure properly for as the dynamic range is quite wide. One option would have been to expose for the shadows in the land mass, then use a Graded ND filter for the sky. One of my favorite ways to handle these types of scenes is to bracket a series of 3 to 5 pictures, then produce a HDR image using Photomatrix.