I absolutely agree with Sarah's comment about (particularly) the first shot being over exposed. Sure you can see the wall real well but at the expense of the top half being way too bright. So bright that the sky has hardly any blue in it and there's lots of PF (and color bleeding) on the top half of the tree due the extreme high contrast. This image would be a typical example of overdone HDR processing. I personally prefer the other images, even though I can't see the wall.