This really depends on at what stage of your career you are at.For a fresh graduate out of school, brand name should have heavier weighting in your decision-making, because you really don't know what sort of work environment/culture is suitable for you. A bigger brand will allow you to jump easier once you have that figured out. (Many of course find their perfect spot for their first job).If you are more experienced, have the brand name already, then just follow the interesting work, the people and the compensation. However, a lot of boutiques are subject to the famine-or-feast syndrome. Exceptions are certain boutiques who just do repeat work for a few very long time clients - which defeats the point of working in MC, since it's variety you are after?