dvds are a standard definition media that stores sd video. Blu-rays are the next gen media for high definition video.

also, blu-rays have 7.1 surround sound and dvds have 5.1 surround sound so blu-rays are better.

also blu-rays are more scratch resistant than dvds.

blu-rays can store more video and special features than dvds.

blu-rays are more robust.

blu-rays are more expensive

blu-rays are rarer than dvds.