Vantaggi
You get to work from home, the culture at he ground floor is great, and you'll almost certainly get to work near the center of IT at large, well-known companies. The networking alone, both with Appirio consultants and with clients, might make working here for a couple years worthwhile.
Svantaggi
The usual growing pains, including unaccountable middle management, stack ranking leading to demotivation of great employees, lack of recognition (read: spot compensation) for work well done. Internal competition lead to many great performers feeling that there's no point in trying. A clique of "golden children" at the middle-management level are perceived as untouchable, and feed their own image, while not spreading credit around where it's deserved.