Pros
I've never worked somewhere that people were more emotionally supportive of each other. Everyone gets a voice in almost every meeting. At the end of the quarter, sales reps are helping their coworkers close deals so they all make quota... I've never seen that before anywhere. Changing the world in a fiercely competitive market, on a startup budget, is intense, emotional, imperfect, and sometimes a little scary. The team is filled with people who are motivated by the challenge of winning as a team, and we're quite motivated. People who have come through and turn out to be more concerned with themselves and obsess over what everyone else is doing wrong, don't last very long. And when they leave, they are bitter and blame their manager and politics. Also, it is a great place to learn everything you need to start your own company. The founders often talk about angel investing in future companies founded by Highfivers.
Cons
Winning can be demanding and intense. Everyone is expected to pitch in whenever another area is struggling. Sometimes this means long hours or hard work that isn't in your job description. But we all do it and it pays off.