its ok..... the letters in all of them are nothing special.
You pretty much made a selection, either made a 5 second background (link one) and then went on to just put it on there. You need to blur the edges a little bit, then you need to not make it so obvious that you just added a simple effect.
here ill go down your sigs
1. I you put the selection down with a glow, pretty simple,you can still see parts of the pixelated edges.
2. good selection, the only thing wrong with this one is that the text is boring, when everything else is great.
3. you chopped off his ear, and that target background thing is one of the defaults for(layers?), but otherwise, its a good high-def render.
4. It would have been cooler, if you would have taken out that giant thing....... and put a Pelican, most of the edges are pixelated(on the chief), but the text is good.
Now im not bein mean, im just giving my critical perspective.