Mathematics is really more an art than a science. Science is about observable phenomena; mathematics has little to do with observation. A good mathematician needs to be creative, able to think laterally. Anything less makes you little more than an accountant. (No offence to any accountants out there.)
Mathematics is essentially the purest form of thought. Some people say that music is the purest form of emotion. But I'd like to think that we've come a bit further than the ancient Greeks in that we no longer think of emotion and rational thought being antipodal. They are really just different ways of approaching things, and they aren't really separable at all.
There is "beauty" in mathematics, on just as abstract a level as we say there is "beauty" in music. On a more "rational" aesthetic level, we like mathematical systems that are balanced and symmetrical, just as we music that has symmetry and balance on the same rational level of aesthetics. Mathematics and music are both highly abstract. This is probably why musicians are often more proficient at mathematics: both pursuits involve abstract thought that can't be expressed in images or language.
Music expresses more "raw" emotions, however this has more to do with the physiological and/or cultural effect it has on us. Of course it is more effective at communicating emotion, because everybody can listen to music, whereas the vast majority of people can barely remember high school algebra. It speaks to a wider audience, and has developed a language that is effective at expressing emotions. Whether this is an inherent property of music is highly questionable. There is no objective emotional content in music; it is found only in listeners who impute it. Whether the response is fundamentally ingrained or purely cultural is an interesting question, but I prefer not knowing, because I would prefer the magic to remain.
There are of course 'mathematical' elements in music, as many of you have pointed out. We speak of melodic and harmonic 'formulas', chord changes that are as guaranteed to evoke the "right" response as certain as a mathematical theorem. The composition process isn't as subjective as we would like to think; there are rules that everybody follows, rules that some people choose to follow, but I think we can agree that if the composer is not writing based upon any rules then s/he is no longer creating music: a computer can create white noise more efficiently.
I'm not necessarily saying that the emotions imparted by music are reducible to mathematical formulae (this is the 'magic' I was talking about), but to say they are totally different is really an unsupportable claim.