As I may have mentioned in the past, the consultant's first job is to find out exactly what it is the client actually wants (or hopes to achieve). Perhaps I have been unlucky, but in many cases the client lacked any clear vision (in other words, didn't have a clue), and the mission statement needed to be coaxed (dragged) out of him.
It helps to actually read the question...
Could anyone recommend or advise on what they use?
Please stay on topic.