The first one shows no contrast at all, which I hate. :/ To be honest, you use too many bright backgrounds and you need to keep things a bit more simple. The last one and the Lucario banners are probably best, and the poke ball one looks crappy bescause of the render. It looks like you just slapped on the pokeball sprites.
Well, practice makes perfect. Good luck~
-MetalGardevoir
watch that little balloon float across the sky