The most important thing first: it's safe and you won't get banned for using it (IF you follow all the instructions and use the cheat properly).
But:
1) The aimbot is not good for playing legit and just having a little assistance. The smooth factor doesn't work with value over 19~20, depending on your FOV. It's sticky and with few options of customization.
2) Your config is not saved and you have to re-do it every time you launch the game.
3) The menu sometimes doesn't close.
So, I think 4 stars is fair because it's safe and not expansive.