I got an ebook copy of 'Gender is really weird' courtesy of Netgalley. This review is my own opinion.
This is a great book if you want something fast paced to explain gender and how it impacts you and the world, and the basics of what language to use. No single book can tell you all there is but this book is a great starting point. There is a page with different gender related pride flags with a guide of each ones meaning which I know I would have found really useful a few years ago when I was really struggling with my gender.
I found it especially interesting to learn about other genders in different cultures. I love learning about different cultures and places and it's fascinating who different parts of the world deal with gender and all it entails, I definitely want to go and learn more about them now.
The part on the gap in information around gender and everything was very interesting too. I have just finished invisible woman so I knew a lot of it already though this felt like an easier format to handle. 
The illustrations are bright and colourful too and make it much easier to read than a big block of text. Loved seeing illustrations of wheelchair users too just casually there on the page as well.
My only problem is sometimes abbreviations seemed to pop up out of nowhere without any/little explanation.
Overall I'd recommend this to anyone wanting to be a better ally, learn more about gender or to someone like me who is struggling with theirs.