Well the fact is that there is no guarantee you will earn $$$ per hour since my greatest frustration was that I could work so hard to see if I could earn, at least $40 in a day but end up with $8-$12. In other words, one may do five assignments under premium level, for works worth $4-$8 per piece then after all that, end up with at least three rejections and two accepted articles. If I were to be asked there is little difference between gambling and working for these people. So hope and pray that the person you write for likes you! I think I've been submitting the best of my works but at some point you can't help but think someone is out to "squash your balls" of writing.
Otherwise, the star rate is because it is very legit!