neither as neither exists. theyre merely constructs of a time when we thought we needed moral compasses in the form of almighty or wicked beings in order to guide and explain things for us.
but if i did believe in these entities, i would have to say god is the more wicked and tricky, he did not want for us to have knowledge but to be naive creatures who worshipped and loved him. it was the devil who showed us the path to knowledge, and has never truly done anything to deceive.
just my 2 cents anyway
Both are far greater than anyone can understand. To know that neither exist, one would have to know about a lot more of the universe than people know now. Why? Using their greater power, both could disguise their appearance so that nobody would ever recognize them.
Nobody knows enough about how the universe works to know that God and Satan don't exist. The thread,
Scientific proof that God exists? - https://bitcointalk.org/index.php?topic=737322.0, shows beyond all doubt that science proves that God exists.
Anyone who looks at the proofs in that thread, and still doesn't understand that God exists, is either in a religion of atheism, or is going that direction.