I am not sure that I completely understood Quentin's section of the story.  It is very hard to follow the plot happening beneath his other thoughts and memories.  But I really like his writing style.  I like the way that he combines the past and the present, because the way he thinks makes sense to me.  Unlike Benjy's chapter, I felt more able to follow the connections between the present and his past memories.
I thought that his obsession with time was the most interesting part of the chapter.  His father says at one point in the chapter that time will make all of his problems go away, and that he will forget what has happened.  I think that partly, he doesn't want this because it makes the experiences less real, but he clearly wants to triumph over time by ending his life.  He has to make sure that time goes on by checking to see that some clocks are exactly on time, but he wants his time to be over.
I also noticed that he seems much more observant about people's characters than the other people in the story.  He is able to sum up his mother's personality in a few words that she spoke at one point about all of the things she has to deal with.  And he perfectly captured Caddy's personality, and her wish to rebel in every way from her family.  He was also able to show personality in the servants of the household.  I think that other narrators from this time period would not have seen their workers as people with personalities, but Quentin clearly understands people more than his other siblings do.
One of the things I can't decide about Quentin's character is if he is a good person or not.  I am not entirely sure what his motives were for protecting Caddy, and he seems overly obsessed about what happened to her.  This could be a sign of how much he cares about her, but it comes off as pretty creepy to me.  But he does seem to care about Benjy, even if it is just for Caddy's sake.