Very nice.
On the first one, I wouldn't leave the horizon in the middle of the screen like that. Either make the sky the star of your show or the ground. Since, in this case, the ground is completely lost, I would have minimized it and shown more of the sky. Perhaps try cropping out about half of the black and see how it looks.
FWIW, I think #3 is the winner of the bunch. The sun is perfectly placed, the clouds have more detail than in any of the other shots and I happen to love the rays coming out of the sun.
Zev Steinhardt