Fake professionalism. The training is a joke. The majority of it is online PowerPoint presentations. The hands-on training for health care is unsafe. Many of the participants are immature boys who lack self-discipline and go absolutely crazy in training for restraining patients even when told to go "50%" resistant for training scenarios. As someone who practices in martial arts, I really find this dangerous. Trainers don't care - they see this as some form of entertainment. Many training sessions result in injuries.
The company hires anyone and everyone. This means your co-workers could be really good but in most cases, many are lazy, physically unfit, and immature people who would not survive in a real professional job environment. Employees would complain when asked to do basic things like patrol the site. Management lacks the spine to effectively discipline such workers, because the business model is based on filling shifts with warm bodies rather than people who care about doing a good job.
Management is frequently out of touch with the realities on the job site. Managers would often spend time at busy, high profile sites dealing with bureaucratic garbage while neglecting medium and small sites.
You get three sick days. Have you ever recover from a cold or flu in three days?
The pay scale is very low. You will be restraining aggressive patients with all sorts of diseases but don't expect to ever see a good wage. When there are problems with payroll, it can take up to month for them to even process your payroll correction request.
Upward mobility, promotion from within, etc. are all an illusion. It's just another effort to minimize wage increases. For example, a shift can have a supervisor, a "senior" officer, and a "junior" office. In practice, there's basically no difference between a senior or a junior (often, they have the same experience and produce the same level of work), but one is paid less. The company can tell the junior that he/she has hit the cap for that level.