Hulu has higher quality video than is on the network sites and also has many, many shows from the past that are not on any other sites. I watch Chuck there instead of on NBC because the quality is better and the site is designed for viewing and is thus faster (the NBC site has all sorts of other material on it).
As far as I can tell, Hulu simply aggregates video; I usually go directly to the sources (the network web sites).
Hulu has higher quality video than is on the network sites and also has many, many shows from the past that are not on any other sites. I watch Chuck there instead of on NBC because the quality is better and the site is designed for viewing and is thus faster (the NBC site has all sorts of other material on it).