Me too, i don't really like Sawako, even in the anime. She's somehow.. uh.. not fitting along with the K-On or somethin'? But she's funny so i don't hate her :) .. (For example i really like that part where she was angry, don't remember why or which episode it was, and Mugi said "Will you have cake?" Or somethin' like that and Sawako: ".... I will!" and everyone was like "O.O" :D)
Mugi's just awesome! ^^ I can't find anyone to pair with her but.. uh.. Let's say that she's just for fans :D (I personally really liked Mugi just 'coz she likes to "watch" yuri just like me :) even in the anime, which surprised me xDD)