Avantages
I've had a lot of great experiences working here. The client list is one of the best you'll find anywhere (New York or otherwise), and I've personally worked on some of the best projects of my career here. I'm constantly learning and I look forward to coming to work a lot more than most people I know. That said, I think the number one reason a CMS developer should consider working here is the overtime policy. If you work more than 40 hours a week and the company can bill for those hours, you are paid for them. It an incentive that keeps project managers honest on estimates and keeps people motivated. It also means the chances of working 12 hour days are pretty slim, which is great for work/life balance, etc.
Inconvénients
I have definitely been assigned to projects that weren't properly estimated and examined before I started working on them. I've also been thrown into situations that were well over my head and I had a hard time getting the help that I needed. That said, most of the other downsides are really just downsides of working in consulting. You don't have a constant office, you may not always like the project you're on, but few projects last more than 3 months anyway.