Pros
POSH is a great company to work for. If you're looking for a way into the private event industry on the entertainment side of things, there's nowhere better to be. The DJs are all experienced in private events, clubs, bars, radio, and beyond and the contacts, knowledge, and experience you can gain here is invaluable if you take advantage of it and work for it. Even if you're not looking to make a career in this business, for a college student or someone with some time to kill on the weekends it's solid extra money. And honestly the best part of POSH is that everyone is pretty much family. Everyone gets along, there's extremely few conflicts between employees, and if you have a comment/suggestion management is very willing to listen.
Cons
If you can't handle late nights, this isn't the job for you, but it's made very clear during hiring that POSH primarily does weddings, which routinely end between 11 PM and 1 AM depending on the event, plus breakdown time. No one should be surprised by this after going through the interview process. Other than that, no cons.