I think the upper one puts the shield in focus. also about shadows, say if the sun is behind the shield, the shadow would be in the first image. The sky though maybe could be changed a bit, if the sun is behind the shield the colours would be more like circles and not as you have done it. I think it nice though, do some polishing and add a cool emblem and it rocks!
I think the second one is bad if you look at composition, the sky break the composition. and you really don't have any good composition at all as we can see in the first one, where all is made to focus on the emblem which is the main thing in the picture right?
Good work!

PS. look out for not have the same colours inside the emblem as outside the emblem, the emblem must stick out and not melt into the background, also I don't know but the colours may not be the best, but I think there are plenty of better artist to help you with that part.
//Albin