Pros
This could all change now that Protection 1 has "merged" with ADT. For now, their pay rates are relatively high for similar positions. There is a lot of opportunity for advancement but... (see cons list). The CEO gets a thumbs-up despite my cons. He walks around and talks to every employee on site visits. He gets brownie points.
Cons
Training and development is not a strong suit, particularly for leadership roles. People who are good at their current jobs tend to be promoted into management, even if they have little to no management skills. There is little in the way of continuing education and training once you reach a certain level. Training and development for lower levels is, at best, "so-so." Get ready to sink or swim. If you are a swimmer, you will likely do well.