Pros
I've worked at a number of agencies, and Media Storm is a different experience by far.
Lots of smart, hard working people. Incredibly strong and inclusive teams that makes it much easier to do great work. No politics or backstabbing. And a bunch of people who actually like working here and enjoy each other's company. I see some disgruntled comments below and they do not reflect the agency by any means.
While most agencies get in a room with clients and promise to solve their marketing dilemma by any means necessary--then produce a bunch of :30's and banners--Media Storm actually delivers on it.
A great variety of work for a great client roster that makes every day interesting and keeps it fresh. Without the 80 hour work weeks. As a matter of fact, most of the agency is out the door by 6.30PM, so YES you can indeed expect to have a life outside work.
Cons
Have a clearer and more rigorous evaluation system of performance to discuss potential promotions