1-$500 is a lot to pay for a piece of shit.
2-Sony was very good until a guy named Kaz Hirai came along...
3-Little features? Backwards compatibility, motion sensing, VC, news, weather, email, and internet browsers. Very configurable controllers with all the add-ons. All packed into the smallest package out of the three contenders.
4-Older people will be attracted. The reason Nintendo is popular with kids is how they think of what the gamer would want rather than shoving blue ray crap in their face.