The cons aren't so much anything dirrectly at the company but at the nature of the industry in general. Security 20 years ago use to be mostly inhouse and thus would pay $20+/h. However since the Recession, and especailly since the privitization of most security (as well as proliferation of smaller companies like Concord, Guarda and the Comissionairs) the wage of the average security guard has dropped significantly.
The fact that security is very important for liability and safety also means that sometimes you may be forced to work overtime, but luckly thats rare (if ever) and more depends on your co-workers rather than the company: while at McDonalds someone not showing up or showing up late just means everyone works a bit harder, in Security someone not showing up or being late causes a huge safety concern in that people MUST stay to cover that position. The company is though really good about if you have prior committments: if you genuinely can not stay late because of committments, let your bosses know and 99% of the time they will work around it
On occasion you meet bad apples within the company but you find that in any company you work in and in my experience Paladin has the fewest or the easiest to deal with.
Security is also mostly a night-time industry (ie: things are generally safer during the day because of more wittnesses) so be prepared to work plenty of nights or late afternoon shifts.