Pros
Highly flexible scheduling: You pretty much just set your own hours and can pick and choose when you work.
Great coworkers: Most are pretty good company and help your shift go by faster. Honestly, they're probably the best part about working the gigs for the events in and around town. Lots of people from very diverse backgrounds, and it's rarely ever dull making small talk with them.
Easy work: Nothing about the job is especially difficult. The hardest parts are bag checking and credential checks, and only because people like to argue with you about why they deserve to be an exception. Otherwise you basically just stand there and don't really have to do much of anything.
Cons
The visitors: As mentioned before, they will argue with you tooth and nail over even the most clear cut policies set by the venue/organizers that's been spelled out for them.
Low pay: Pay is pretty much peanuts in all honesty, you're lucky if you can find an event that'll pay $15/hr, most events tend to pay $12/hr and anything that pays higher than $15/hr is extremely rare.
Hours: While the hours are flexible, the supervisors are infamous for cutting people early to save some dough. Fine if you're only doing the job as a side hustle, not so much if you really need the cash to pay your bills.
Physical strain: While the job itself is easy, you will be on your feet for hours on end, and you'd best have some really good insoles in your shoes. Sitting often tends to be frowned on by supervisors, and I myself have had to do 12hr stints entirely on my feet with no sitting allowed whatsoever.
Breaks: Often very inconsistent at best, sometimes nonexistent at worst. It's especially bad if they're shorthanded on an event, and god help you if the crew is short on something really hectic like a concert.
Inconsistent leadership: Supervisors here can be really hit or miss to work with. Really loved working with the great ones, and to the company's credit most of them are, but it was always a drag working with the ones that were either incompetent or on a bit of a power trip, or worse, both.