My Take
Mathspace is quite an average app for learning - there are definitely better apps out there. It also caused several of my students to indulge in some... self-harm. I caught one of my Year 9 students using a disassembled sharpener razor to cut her arms. When asked why, she claimed she couldn't take the pressure of Mathspace. One of my Year 7 students walked to the front of the class whilst I was out of the room printing math worksheets, and he took a sharpie, wrote on my whiteboard "MATHSPACE MADE ME DO THIS" and proceeded to take 48 Aspirin pills along with a shot of vodka. I came back to the horrific scene of his unconscious body, thankfully he survived, but after these horrible experiences with Mathspace, I recommend you do not use Mathspace as they can place unnecessary pressure and stress on already hard-working students. Of course, if you believe your students can take on Mathspace, by all means - go for it - but seriously, Mathspace can seriously impact your student's mental wellbeing.
How I Use It
I assign tasks on mathspace for students to complete their homework. I can see their progress which is quite useful, but I haven't really seen a change in grades ever since I began using it.