Pros
They're very flexible and open in testing and implementing new technology that may improve productivity and efficiency if it's within their budget. You have the freedom to handle your tasks any way you'd like as long as they're completed within the shortest possible time frame.
Cons
They do not offer any medical, dental, vision, or retirement plan. They often change the way things are done within the company as you work along. Employee who couldn't keep up with the constant changes or work slower than rest of the group are usually let go shortly.