Pros
G4S has reliable work for what they do
Management varies wildly - I enjoyed working for the people I worked with, but other teams suffered morale.
If you want to become a PI, this is one of the best companies to get your experience with and see if you can handle the work.
Amos Nessim is amazing and other managers need to model themselves after him.
Cons
Advancement opportunities are limited
They are the lowest paying company I've ever worked at
Too many good SIU Investigators are suffering in surveillance and vice versa.
HEalth insurance was abysmal for front line investigators