It's a great place for students to stretch their intellectual muscles.

It is a good tool when the students have first practiced a topic on paper and just need some additional review prior to an assessment. Would be useful to those who needs a bit of addition help on their schedule. Most people can just use the free version.

I wouldn't recommend it due to their lack of support through billing. One cannot even remove their payment information from the account.

My overall opinion regarding this project as a teaching tool is that it, in the correct hands, could be a very beneficial teaching and learning tool. The free version is good enough for most unless you run into a problem that becomes difficult to solve. The solutions and solving process are only available via Brilliant Squared (a subscription plan of $4/month billed annually). It is a good tool when the students have practiced a topic via worksheets and just need some additional review prior to an assessment. In fact, the website would possibly make a good assessment vehicle: the kids could copy a problem onto their own paper, or take a picture of it with their phone, work out the solution in small groups or independently, then submit their agreed-upon solution to the site. Also, I have used the site when creating short teaching videos of specific skill sets via the SmartBoard with iMovie on the iPad.