Pros
Opportunity to learn many different technologies and take on new roles and responsibilities. Even though the cons I'm about to list might scare you off I actually do recommend to interns or even full time for a short time because the kind of experience you can accumulate here in a short amount of time is astonishing. Plus, observing poor management in action can still be useful as a what not to do lesson.
Cons
After 2 years or so the shine wears off and you start to notice how poorly management runs the office and how little trust and respect CEO has for his employees. The CEO sets the tone for the office environment and the behavior tends to trickle down to those around him. It's a shame because he's a brilliant technologist and salesman. If only he could be a leader the company could go a lot farther.