Pros
best client relationship you will find in adland. generous budgets to produce big scale work. AMAZING offices and views (you will be working in one of the best offices in London). best people I have come across in this industry.
Cons
one client set up means only specialising on Ford mostly. but the upside is that you will get to be truly integrated across PR, digital, social, TV etc. although not a con for me, some people may feel that this is not the fastest paced environment in adland. It is down to the individual to shape his/her role to feel it has pace. your career and scope for progression will truly be in your hands. I went for it and made a great a addition to my CV which contributed to landing another great job 5 years down the line