Pros
Coworkers are friendly. If you have a well-defined role, the job could be manageable.
Cons
Very very very poor communication, borderline chaos. There are a few good people there who do their best to bring the semblance of order.
The CEO comes up with an idea about every four hours for something completely new. In the same conversation where you are being told about this new idea that you've never heard of, he is getting frustrated and even upset that you haven't done anything about it. Ten days before I even began the role, I was asked in a phone call without any prior notification what I had been working on in the way of a administrative development plan for the new business location.
I was told there would be some late hours, and even some weekend hours. This means being able to drop your weekend plans 24 hours beforehand for conference calls on a Sunday. It also means being able to stay late on any given night for international conference calls on your own cell phone because the office doesn't move a company phone into the room.
Chaos and clinical trials do not go well together.