This is actually an interesting question. Really, it depends entirely on what perception of the stories you subscribe to. There are multiple interpritations of the devil throughout theology and literature.
First off, there's the idea that the devil is the lord and master of Hell, and controls all that goes on in it. Therefore, he would be fully capable of making hell into a nice place. But then, that also depends on what you veiw to be hell worthy. Is it simply being a sinful person, such as doing bad things to other people, or does it encompas not following the church. And then, you must also take into account how you veiw the devil in terms of personality. The funny thing is, there are almost no instances in the bible where the devil is presented as being sadistic or cruel, and thus no evidence that he would at all be proud of or ally himself with the Hitlers and Stalins of the world. All the devil did, in the bible, was question god. Now, there may be instances I'm unaware of, but to my knowlege, he never directly harmed anyone. In the book of Gob, he simply asked the question "do yout followers truely love you, or do they simply say that they love you because you give them the things that they want?" That is, actually, a rather good philisophical question in of itself. When he tempted Jesus in the desert, he did just that. He tempted him. He didn't hurt him in any way. He simply asked "Well, why does it have to be this way? Why can't you do it another way?" And, of course, in the book of Genisis, all he did was say "Hey, what would eating a stupid little fruit hurt?" The only depictions of the devil as a true monster is in the book of revelations, and even then, it's not the devil that does the mass murder, it's his son. The devil was simply meant to show the rebel. The person who questions the status quo. It's just, to many, this is considered to be a bad thing, so he is thus considered to be evil. So, one must ask the question. If Satan truely did have the ability to make hell into a good place to be, would he want to? Would he want to reward the murderers and rapists who end up in his domain? Would he identifiy with them at all? Or would he be just as disgusted with their actions as we are?
Then, of course, there are two other interpritations that I can think of, both of which throw the idea of the devil controling Hell completely out the window. One is that he is banished there with the rest of the demons and the damned. He has no power to leave. He may be the top dog in the prison, but he's still a prisoner.
The other is that he neither was banished there nor does he control it. He simply quit his place in heaven, and went to live in hell because it was simply the only place left to go. While he quickly atained a possition of power over the demons and the damned due to his imense power, he does not control hell, he did not create it, and he has no ability to make it any better or worse than it is.