You are a contracted employee, so there are no flight benefits. The uniforms are horrible, very cheap and itchy, and you must put a $150 security deposit down when you first receive it.
Each airline has a separate Hallmark business manager, and the quality of the manager will vary. Some managers have no leadership qualities, others might.
There is a super high turnover rate with the employees, but it also depends on the account. Some accounts have long standing employees, others do not. It can become very depressing when everyone around you is unhappy with their jobs.
Your pay will be VERY little, especially for the work that you are expected to do. Most accounts start you at $10.50 per hour. You will most likely start as a part time employee, with an average 4.5 hours per shift. After the first 90 days you might be able to pick up another account, but it depends on the discretion of your business manager. If you do choose to work more than one account, you will have no work/life balance. Working full time (which is less than 40 hours for hallmark), will exhaust you, and you will average less than $350 per week minus taxes.
Scheduling sucks, but it depends on each account, and which days/hours the airline account flies.
Also, depending on the airport, you might not have access to terminal parking. Hallmark "provides a shuttle" that is unreliable and broken down, usually without air conditioning. Which means that you might have to arrive 30 or more minutes early to catch a shuttle that may or may not be there on time. You will also be smashed into the shuttle with 15 other employees, kind of like sardines in a can.
You can become a lead agent fairly quickly if you work hard, but to become a supervisor or an account manager you have to dedicate quite a bit of time to the company. If your goal is to work in the airline industry, you are better off applying to work for airline staff if you want to reap in the benefits of the industry.