It's like the mini-planets from Ratchet & Clank! I love the cute little clouds and what appears to be a planetwide rail system. And the background of stars and the nebula looks just awesome. Lovely work!
Just beautiful. My brain says that if I'm far enough away from the planet to see the curve, the clouds should all appear to be at the same altitude... but that's for regular-scale planets, of course (and assuming that air pressure varies according to gravity as it does in our universe). I like this sort of idea, and this is well visualised.
... wow, this is beautiful. The detail is absolutely impeccable. Some of these renders you have in your gallery are great but this is definitely a favorite of mine. From the clouds, to the stars, to the leaves on the trees and the rocky surfaces of mountains. The detail is wonderful and the feeling that this image gives you is great. You've really created an inviting world of your own.