In the grand fashion of taking an old TV series or movie and revitalizing it, this show found its start. From the impressive miniseries, the tumultuous episodes of season 1, the peace and tragedy on New Caprica, the elation over finding Earth, the devastation over finding Earth, to the timeless series finale, this was an amazing emotional roller coaster of a series.
One of the best aspects of Battlestar Galactica was that, unlike other popular scifi series, characters were never safe. In the 28 seasons of canon Star Trek, only 3 main characters died; Tasha Yar, Jadzia Dax and Trip Tucker. In the 4 seasons of Battlestar Galactica, at least a dozen major characters died. This kept the show fresh and unexpected.
Viewers found themselves emotionally vested in the characters. It was like we were sharing these people's tragic lives every week. This was a new breed of scifi, a bold new future for the genre.