I have also seen Stick It, Make it or Break it, and part of Nadia. Also, I saw Little Girls in Pretty boxes. Books, I just finished reading Winning Balance by Shawn Johnson, and I read Chalked Up by Jennifer Sey a while ago. My opinions:
Stick It: My favorite gymnastics movie! I found it funny and fairly realistic when it came to the gymnastics part. Except that *spoiler!!!* they all scratched at a big competition. Seriously, no one does that. But props to them for getting it right that gymnastics is extremely unfair!!!
MIOBI: Ugh. What to say. Well, I'm not the best judge, because I never made it past the first season. Couldn't stand it. But while I didn't watch the rest, I read Spanny's hilarious recaps on her gymnastics blog. From what I saw/read, it was awful. Not realistic, and it was about the girls' drama instead of gymnastics. For non-gymnasts, it would be okay. But there were soooo many mistakes! Like trying to pass off a double back for a triple back. Really???
Nadia: As I said, I only saw part of it. And that was because I just couldn't make myself watch the rest of it. Ugh. The acting was terrible! And, correct me if I'm wrong, but I am pretty sure they got her "first perfect 10" routine wrong. I am fairly certain that the real routine was the compulsory routine, and they showed a different one.
Little Girls in Pretty Boxes: Again, ugh. Acting wasn't great, neither was the storyline. Quite boring, but I did manage to watch the whole thing. I found the last scene pretty funny, where the girl is walking on the high beam, and her mom is like, "can I spot you?" And so she holds her hand and "helps" her walk down the beam. Last time I checked, that was for little kids, not elite gymnasts.
Winning Balance: Personally, I loved it, but I'm a bit biased. Shawn is my favorite gymnast ever, so I love anything about/by her. But I liked how it wasn't just a plain autobiography, with just the plain hard facts. She told little stories to go with all the big events, and also she talked about the lessons she learned. I learned a lot of new things about her that I never knew. I found it very inspirational.
Chalked Up: I thought it was pretty good, but I read it when I was about 10, so I didn't understand parts of it. I think I might enjoy it more if I read it again now that I'm older. Now that I think about it, it probably wasn't a very age-appropriate book for a 10 year old... But my mom was reading it, and I saw that it was about gymnastics, so I read it.
So, yeah, those are my opinions on them.