Compared to Dragonflight and Dragonquest, Dragonsong is more young adult oriented. I think McCaffrey does much better in this style because she focuses on the emotions and motivations of the main character, Menolly, rather than being caught up with the plot.
This is a great book for teens because it features a protagonist that has a deep passion for music, but is ostracized by her family and community, and must practice in secret. I think this is something most teens and young adults can relate to - really wanting to pursue something but having others stand in your way and put you down.
Menolly is pragmatic and hopeful. I enjoyed her character immensely. I thought it was realistic the range of emotions she went through, and she did grow throughout the story. I think it's unrealistic for a young character to be constantly defiant. At some point everyone gets downhearted and depressed when the odds are stacked against them. I also liked how there wasn't a romance story or a boy that was interested in Menolly. I think that would have detracted from Dragonsong because the book is about a young girl finding her place. A girl can always do it on her own. Doesn't always need a boy!
Dragonsong takes place in the same time as Dragonflight and there are some references to one of the hatchings in Dragonflight. Other than that, if you are following the main Pern storyline, missing this book isn't going to confuse you later on.