It launches faster, some people like the aesthetics more. Some people claim it's faster at web surfing too, but a lot of people dispute this, myself included. Javascript benchmarks don't count.
Try it out, if you like it, use it, if you don't, don't.
Doesn't seem that different. One thing is that Firefox would often quit on me when I had multiple tabs open which were doing a lot (like checking games on nfl.com). We'll see how that goes with Chrome.
