IMO you should watch this before watching season 4
Full Review:
The movie was not bad - the only part that I found slightly annoying was the one that involved the young Bill Adama (very unconvincing IMO).
The scenes with and about the hybrid were pretty captivating and the show needed to fill that gap IMO (and it did it nicely in this movie). I would recommend watching this movie if you're planning on watching season 4 (which you probably are:) )