I've heard many Christians who do not even believe in Satan or hell. There are a few view points like that, so I know they would not believe in anything at all concerning him of course.
Satan...IF he does exist. He would have to have some kind of ability or power, that God can not control completely. If it could be controlled, then no one would suffer eternal damnation in the fires of hell! If all temptation and evil comes from Satan, and God can control Satan, then ultimately, God allows such a thing to exist. That is very sad, that God would have us burn in hell forever if our gift of free will was missused. So, I'll say that God can't control him completely for this thread.
Satan is interesting also in the matter, that all angels were created by God, to love and serve Him. When did Satan or Lucifer, suddenly gain the ability of free thought and free will? How can ANYTHING in the very presence of God, turn against God? And there were other angels who turned against God also. (Wonder if any souls from Earth has ever turned against God??)
Who's to say that Satans miracles aren't preformed everyday? Some may actually be good things. When he tempted Adam and Eve, he was trying to have us gain knowledge of right and wrong, good and evil, etc. That was quite a miracle that he was able to tempt us and God not know Satan did it...b/c it wasn't too much longer that God came to the garden asking questions of Adam and Eve. It also did not sound like God intended for mankind to become what we are.
Sorry, I'm getting a bit off topic, but think of the wide reciever or running back for your favorite pro football team. When they catch that winning pass, they give God the praise and thank Him for helping them catch that ball. Who knows, maybe Satan keeps some from catching the winning touchdown, so that they lose. But you never hear anyone saying that in public!! Maybe Satan created the AIDS virus or the common cold. In our society in America, many good things are attributed to God. Many bad things are attributed to Satan. Maybe that's the miracles he performs.
I guess Satan doesn't do more for his cause b/c maybe he does all he can. Some say God speaks to them...maybe Satan speaks to some too. Maybe Satan does a few good deeds to seem as God for those who see, then leads them astray. That's very powerful. Maybe he already has the large majority of people heading to his gates with his deception already. If monotheism is the answer...there are a LOT who are wrong.