Not bad. The bottom two are kind of big and bulky, but yeah, overall they are nice. Also, are you sure you made that Ratchet & Clank one? I could have sworn I saw it on Planet Renders during a SOTW several months ago...
They are good for a start, but make them smaller the next time, and improve the text, furthermore, where do you get that Silver render?
They are not bad at all, the bottom two are gigantic but that all. Work on some foreground effects such as clipping masks and C4D's to add depth to it. As well as sharpening and blur tools. Sharpen=Foreground. Blur=Background.