I like them all. But here is the catch, the colouring style of October's Edge would be kind of out of place in Falling, and likewise vice-versa. They give different feeling to the artwork that affects the overall mood of it.
For me I'm cut between October's Edge and Falling, the first being bolder and more eye-catching while the latter more sketch-looking. If I had to choose, I'd do the first mainly because I'm a bigger fan of more "powerful" (:iconitsover9kplz:) colors, where as the latter has more faded colors.
I like the autumn picture the most, but I really think you should continue playing with different coloring styles, since I like them all and it makes me really excited when I see you trying new stuff. Your style is very dynamic and it makes watching you very interesting!