Pros
they promise you to work 30-40 hours per week but they put you some days they want in reserve, that means that you will never know how much you are going to work and they can do whatever they want with your time. reserve means that day if dont call you, you dont go to work, and there have been months only working 20 hours per week.
Cons
they lie about the hours, they promise you a full time job but with the reserves it is only if they want to put you some days. it have to be 5 days working in a week but because of the reserve many people only work 3 days maximum.