My Take
I really like that students can receive immediate feedback in class on their behavior. I also like that the website comes with lots of resources- everything from avatar cutouts to parent letters and invitations. It really comes down to how a teacher implements it- you have to be consistent, you have to use it along with your school's behavior system as a supplement, and you have to communicate to kids what you are doing. We "practiced" with it a lot in class to begin with- lots of roll-playing out good and bad scenarios and what would happen to your Class Dojo avatar if that happened, etc. Changing the goal at the end...whether it be a class party or 5 extra minutes of recess or everyone reaches 20 Dojo points...is good to do on a regular basis as students will get bored with it.
How I Use It
Class Dojo has been implemented pretty much across our entire school building with all 1st-6th grade teachers using it. It is nice to have a whole school involved because teachers can share with classes with others, so even during specials time a P.E. or music teacher can log in and continue feedback with the class. Most teachers have shared the page with parents, as well as "invited" them to look at their wall...similar to a Facebook set-up with updates, pictures, and comments. It is a solid way to replace a class marble jar or earning letters to spell a work for the week, etc.