A lot of people have noted that best thing about Blu-ray is seeing "new" versions of old films in the format.
"Jaws" doesn't qualify as a really old film, but it did first hit theaters in 1975, so it's certainly an older film, and it looks truly impressive on Blu-ray. This is one of the films that Universal has chosen to restore for its 100 anniversary (of Universal, not the film), and some of its earlier restoration efforts have been lauded while others have been criticized for introducing too much digital noise reduction and smoothing things out too much, so the films look less like film and more like video. (Alas, today's audiences are averse to an abundance of film grain).
Such is not the case for "Jaws." I projected the film on a 100-inch screen using a $3,000 JVC DLA-X30 front projector and was immediately struck by how detailed and vibrant the image looked, with an ample amount of light film grain and only a few blemishes along the way. The water and backgrounds feel like they have more depth to them and the color feels just right (OK, the bright-red blood in water looks a little fake, but that's because it was fake).
The sound has been remastered as well, with a new 7.1 surround remix of the original mono track (that original mono version is included in the DTS 2.0 track if you want to hear the movie that way). While purists tend to greet such remixes coolly, this one comes off very well, especially during the frantic beach scenes where panicked swimmers exit the water en masse.
As far as extras go, there really isn't anything here that wasn't on the DVD (and some goes back to the laserdisc) except an 8-minute video, presented in HD, about the restoration process for "Jaws" that includes comments from director Steven Spielberg, who says the movie looks better on Blu-ray than it did when it played in theaters back in 1975. You also get a digital copy and Ultraviolet copy, which is nice.