My Take
This is a great variety of coding projects, and they add new ones often, which will reach a wide variety of students. Beware if you have older computers (and many schools do) as it will bog down your system and cause it to run hot after a while, sometimes resulting in crashes. Don't be afraid to use this with boys, the project page does not specify gender, even though this is supposed to be geared towards engaging girls in coding, as boys enjoy most of the projects equally.
How I Use It
I use this when teaching coding in my computer science classroom. Although Google specifies this is for girls, it doesn't state that anywhere on the made with code portion of the site, so it is easy to use with both boys and girls. There are some issues running on some browsers (firefox doesn't seem to work with a few of the projects for instance) and if you have an older computer it will tax the RAM and cause the computer to eventually bog down.