Not worth it
My friend had one by a different brand, I saw this on SaC and grabbed it. returned it, this thing doesn't work well at all. I'm incredibly not flexible so Sitting with my legs straight out does not make a perfect 90 degree angle easily. I;m a light guy (135) but this thing was uncomfortable and couldn't really support me. It would be fine with your back against something but otherwise... not my cup of tea.
Construction seemed really good and the green looks nice, product just wasn't for me.