Pros
Securitas will take care of your educational needs, in regard to security work. They offered me free CPR, Baton, Pepper Spray and Hand Cuffing certs. They also offered a free guard card cert and renewal. Their pay rates are about average to above average for security work. There is upward mobility options, for example you can make your way up to handling contracts if you stick with them.
Cons
At a low level you may often find that your better at your job than your supervisors. Also some of the positions are not worth the risk. I worked in the hospital setting and was paid $14 per hour to carry a baton and deal with high risk patients and visitors. This meant that if someone walked in with a weapon it was my job to handle the situation. This meant on a daily bases I was risking my health and also possible lawsuits from people I encountered at work. This is not worth $14 and hour. There should have been a minimum of $25 per hour or more.