NUmber 2 is the best for me.
As I did some fairly heavy critique on your last set, I have to say these are a world away. Your moving away from snapshots and thinking about what you want.
The timing on the last 3 is great, just in mid air, but if you were the other side of the jump, you would be shooting the sunny side of the horse, rather than the side in shade. THis would show much more detail in the features of both the horse and rider. It doesn't help you have a dark horse in the shot.
If I am being really picky about the first shot, because you have a dark horse, the sky as the background is great, but the horses face has tress behind it, which just make it a tough harder to see. If it had been nice blue sky, that would be a really crisp profile of the horses head.
Also with 2, as you have the MP to crop the shots, try and not to zoom quite so much. The tail is slightly chopped off, I don;t think it detracts from the photo, but would add if it was all in.
Now go and get some more, show us how you can improve again with the next set.
Well done.