My Take
I love Lumosity, because it is free and it is different from other programs. It is engaging for students and its an added challenge for kids who are tired of ELA and Math. I like the interface and the game are intriguing.
How I Use It
Students need logins, which is always annoying. I would use this during downtimes to improve students' brains. It doesn't deal with actual Common Core content, but it will help them overall. It can be used to focus on memory, speed, attention, flexibility, and problem solving. I would have students use it individually.
I think this is an excellent break for kids, something they can do in-between or after they finish their main work. I would also use it at the end of the day when students have checked out for the day.