Pros
The money is a decent day rate (though not as great as they make out as you don't get any benefits or paid time off). The interview process is straight forward.
Cons
This is not a job for anyone who needs security. You can be let go at any moment; and are under constant threat. Targets are unrealistic. Unnecessarily complex processes. The client doesn't care about the people that work there. All they are interested in is whether they are making their stats / targets. Senior managers on the project are vastly overpaid and are on a power trip. You are told it is a 37.5 hour working week but you soon find out the expectation is to work a lot more and to not leave until you have finished your 'target'. No rights as you aren't an employee.