Bush wasn't evil. I don't think he sat up at night dreaming on how he was going to flambe Iraqi children. I'm sure he didn't rub his hands gleefully when planning to construct Gitmo, thinking "I wonder how many innocents we can cram into those cages ahahahahaha!"
Bush, in my opinion, was under-qualified. I seriously think he did not have the ability to run the country and that a lot of his advisors knew this and manipulated him. He was also fairly lazy, arrogant, self-assured and saw the world in an EXTREMELY simplistic way (you's either with me or ah-gainst me').
Having said all that, again, I do not think he strove to do harm. I do not think he was racist. I do think that SOME of his ideas were good, and that he did pass some good laws (such as a law to create the world's largest marine conservation area).
But he was too arrogant. In his mind, he was right and that was that. For instance, in the Iraq war conflict, I think he genuinely thought that Saddam had weapons of mass destruction. I mean, saddam had them in the 90's after all. Bush thought "Saddam has them", formed that opinion in his mind, and refused to listen to the considerable evidence that pointed out that Saddam had, in fact, destroyed the weapons a long time ago. Bush was waaaaaaaaaay too self-confident, believing in his own version of things, only looking at evidence that agreed with him.
So to sum up:
1) He did not do a very good job. Didn't do the world's worst job either, but his stuffed up a LOT
2) He wasn't evil or the devil or hitler. He was a misguided, under-qualified, simple minded bumpkin who got used by members of his administration.