Pros
The friendships you make with other investigators along the way. Some fun competition between everyone on the field team. Those are really the only Pros.
Cons
Most of these 5 star reviews are fake reviews written by management to boost their approval ratings. That should tell you how shady they are. The office I worked for is extremely toxic with upper management constantly throwing investigators under the bus to preserve their own reputations. YOU CANNOT TRUST ANYONE FROM MANAGEMENT. They will encourage you to break traffic laws and yell at you when you don't. This is the most unprofessional company I have ever worked for in regards to how they treat their employees. Also say goodbye to your social life, your dog, your girlfriend and the gym. You can earn bonuses for good performance...IF management likes you that month. They messed with my pay in their favor and when I called them on it, they fired me instead of doing the right thing. Additionally they lie to their clients, but that's pretty normal for all the national PI firms. A year and a half later I'm still recovering from pouring my life into this job and working within this toxic environment for 3 years. If you really want to be a PI, look for a small company to get started with.