The Seroquel made a major difference although it took about a month before it 'kicked' in.
He still gets angry, sullen and grumpy for no apparent reason. Or rather his propensity for getting upset over things that most people wouldn't, so can be hard to figure out (i.e. I didn't cut the crusts off of his bread - although he didn't ask nor has he ever indicated he wanted them off).
With the Seroquel his anger issues and rage have reduced to a livable (for me) amount. Before there was a fear of him becoming physical as he would get so enraged. Fortunately it was just 'things' that got his attention.