Thanks fuzzylogician, you made some very good points.
Both schools have good success rates, so this wouldn't be a decising factor for me.
With regards to the distance from home, if I attend school Y, I probably won't visit home more than once. If I attend school X, I probably won't be visiting home in those 2 years as I don't think I'd be able to afford it. This wouldn't be a problem in normal circumstances. The only thing where distance might be a problem is if something happens at home (God forbid) and it takes me forever to get there (assuming I could afford the flight). Then again, this is just hypothetical. So I guess it's not the major issue upon which I should base my decision either.
My major concern is that since the field I'm entering is relatively new for me, my research interests are not well-defined yet. Program Y would give me an overview of many areas within the general field before I make a choice (and the program is specifically targeted towards students with a background similar to mine), whilst program X might require me to restrict my choices right from the beginning. I contacted a Prof. at school X about this and I'm waiting to hear from her. So I think this might be the decisive factor for me.
That said, I have to admit that for various reasons, I'm more excited at the prospect of starting program X rather than Y.