Very cute movie, didn't really have any expectations, but I found it very entertaining. A lot of the criticism I read here sounds like it's from die hard SH loyalists or people who don't seem to know this was based on a YA series and were expecting more classic Holmes. The target is more family/young people so if you're expecting serious PBS-style plot, you'll be sorely disappointed. To me it seems like it is what it is - a fun action/adventure for young people vs. hard core mystery solving. This isn't Benedict Cumberland's Sherlock Holmes.
MBB did an excellent job! I mean, I liked her in Stranger Things but still saw her as a child actor. She really shines in this and shows she has range and a lot of charisma. Yes, there is a somewhat female-power theme but I don't feel it was shoved down my throat and I'm usually aware or annoyed by that. She wasn't some rah rah women empowerment, she just was who she was, which would be unusual for the times in a female (or probably even in a boy).