Pros
The obvious : You get paid to travel around the world, and domestic flights are free in your off days. International is cheap. You get to leave work at work. If you have an awful crew, you may never see them again. It's the most flexible job in the world. Tons of free time.
Cons
The pay is abysmal. It's exhausting to fly enough to make decent money. Unless you just LOVE the job and HATE having days off, expect $20000 or less your first year. Things are constantly getting worse at this company. Pay isn't what it used to be. Crews aren't as fun as you expect them to be. 75%+ of the workforce gets to a hotel and locks the door and you won't see them until it's time to go. Layovers are not always in fun areas, and the locations are getting worse by the month. Layovers are shorter than you expect. Being on reserve will make you want to quit. You need to know your contract backwards and forwards otherwise they can and will abuse you. They treat you special in the interview and training, but once you're on the line, you're just a number to them. Sleeping is hard. Passengers will make you a meaner person. Co workers will make you a complainer.