Pros
If you are a client, you're in for some great work at a highly competitive price. If you work here then you will be intellectually stimulated by the briefs through the doors and the sense of comradery that comes with a busy pace and some sky high expectations. You will also get a Mac and some nice coffee.
Cons
If you work here, you're in for a really tough and often exhausting ride. You will learn at an exceptional pace as mentioned above but this will often be of your own volition with little expertise passed down from the top top level. There is always the pressure to win new business based on the ad-hoc business model. This isn't unique to the industry but what is unique is that you are made to feel that the success of salaries being paid lies squarely on your shoulders. The burden of this would be doable if you felt appreciated but sadly you are not. You are disposable and if mistakes happen (which they will as you'll burn out) you are made to feel like you have directly let people down. This creates a fear and striving culture and I'm now certain it's purposefully done to try and get people to give everything over. But this is completely irresponsible. People burn out within 9 months and this is then spin doctored. If you do want to work here then have a get out plan up your sleeve after a year.