Pros
Some nice people to work with, and if you negotiate, you may be able to get paid upwards of 18/hr. Steadyish work for steady pay. Quite a flexible time-off system as well. Decent benefits.
Cons
As mentioned by others, there is extreme nepotism, which you can either work against or with. If you know someone there or get friendly with certain people, you can expect to move up. Otherwise you won't get anywhere, as almost everyone in upper management is either related or knows the family. Most of the bosses are related to the CEO, so if you get on their bad side, you're essentially in limbo. They also expect you to not discuss your pay with others, which is an illegal requirement. This is likely because all the assistants are paid as low as possible and most are on different hourly rates. The Project Managers, meanwhile, earn around $100K. Your experience depends heavily on which boss you get.