Pros
Not really much to say other then that if you like working 12 hours a day just for only 3 days in one week and then 4 days the next week, you're not really making enough to cover income.
Cons
Not guaranteed overtime. You could sign up for it and the odds of getting it is very limited. Not guaranteed to get hired on and they could end assignments anytime. You don't make that great of a pay and even if you do get hired on, your options are very limited when it comes to be certified in different areas and you don't have a choice to where you want to be, you end up being in a position that you don't like due to poor management.