Pros
Large variety of interesting, hands-on work to build up skills as an early career professional. A lot of freedom to own a project and see it through as long as you have the passion to go after it. If you are self-driven and want to work on interesting technologies, this is a great place to be. Many of the people you work with are passionate and dedicated to the work they are accomplishing. If you are looking to put in a standard 9-5 grind everyday, this is not necessarily the place for you.
Cons
It is challenging to be successful at PSI without a PhD. While it is not impossible to succeed with just a Bachelor's degree, emphasis is placed on the degrees that you have. There is not much structure in place to help you build your professional foundation at PSI. The philosophy of management is not to change the way you work, it is to have faith that you are already successful having gotten through the door and that you will continue to be successful while here. This can be listed as a pro or a con depending on your own ambitions, but for an entry level employee, this is more likely a con. Since this is a small company, you will inevitably get your hands dirty doing tasks that are not within your expected scope of work. Don't expect otherwise, regardless of qualifications.