Congratulations! I was also accepted to UW (photo). The funding they offered me was is one quarter per year with a TAship, which means tuition waiver, 5k stipend, and healthcare. And the other two quarters per year vary. They offered me in state tuition (about half of out of state) plus a small stipend.
And the difference between a two and three year depends on the person. I liked the idea of a two year, and having to push myself to develop my work faster, as opposed to a three year where I feel my work would start to stagger near the end.
Of course, some people need that extra year. If your other uni is a three year and a program you love, then you should choose that one. I hope this helps!