Vantaggi
Depending on who is your immediate manager, it can be a great place to work. You can have freedom in technologies you use and your voice will be heard. You will be appreciated greatly if you do a good job. Great office location and environment. People are very friendly. You get a free gym membership.Most importantly they are growing fast and it helps to be part of a rapidly growing company. Also if you do a good job you can get promoted without typical loops and hoops of big corps. Great work life balance depending on the phase of the project and your role in it.
Svantaggi
They are not good in raises and merit increase rate. You have to be pushy in order to a get a raise or promotion. They focus too much on being Advertising Agency than being a Software Company, hence technology people would feel left out of company's focus sometimes. But that being said you would still be heard and can put influence in the corp.