Pros
Employees who have invested their time and loyalty in the company are very knowledgeable, great to work with and understand the systems they support.
Cons
Constant uncertainty if you are going to have your job next week or not. No matter how vital your job is or how good you are at doing it. What ever position you have or career path you are on can be changed by management and you will be doing something that is completely unrelated to your current career path or skill set. The promise of training or providing you with the tools to succeed never materializes. If you bring to their attention they are not following through with what you were told. You will hear, we are the masters of our own destiny. You can go work somewhere else if you are not happy here.