Go back to #3, the cloud thing looks great, the curves really contrast nicely with the angles of the bird; maybe smooth it out a bit though.The wings look nice, but the top half lacks volume in comparison.Also, nice colours.
I must say I really dislike the faux graffiti splodge styled background - I think you could get some really interesting shapes and forms into it if you went further with the detail. I'm imagining a larger array of smaller bubbles, more curves... hmm hard to explain. Not keen on the large cirlces and straight drips. Love the bird.