Voldemort

***SPOILER ALERT***

I re-watched Harry Potter and The Deathly Hallows Part II this morning and I find the depiction of Voldemort to be more morally complex in this picture than in the others (I can't speak for the book which I've never read). What's surprising in the movie is how merciful Lord Voldemort is.  I've been told over and over again that Voldemort is the utter personification of evil, but this just doesn't seem to bear out in the movie.  On three separate occasions, Voldemort makes deliberate decisions to spare the lives of the "good" magicians at Hogwarts.  The first time when he gives them an hour to turn over Harry, clearly giving them an optimal timeline to establish a robust defense of Hogwarts. A second time when he pulls his forces entirely from Hogwarts in order to spare their lives if, once more, Harry chooses to face Voldemort one on one.  And a third time after Harry is "killed" and he offers the students and professors at Hogwarts the opportunity to switch sides. In many ways, Voldemort, at least as he is depicted in the movies, is closer to Magneto than other more "purely" evil antagonists (someone like Megatron comes to mind as being purely evil - the cartoon character, not the movie character. Michael Bay inexplicably stripped ALL of the Transformers of their personalities, a momentously stupid decision, but one to be expected from the world's worst director). Those readers familiar with me probably already realize that I sympathize more with Magneto than that sap Professor X. Or at least my sympathies lie with Wolverine who generally does the "right thing," but has a healthy skepticism of the motives of man.

My question is this - in the books, is Voldemort more clearly "Evil"?  I know he hates mudbloods which is purely racist and not to be tolerated.  But in the end, he seems likely to even spare their lives. Am I interpreting this correctly?