That had its rewards and it's downfalls. Right now, I design packaging for an ad agency. I work on an hourly basis, as opposed to being full-time on salary. They place you on-site in jobs that can last a month, a year, or a week. I've found that the majority of people in this business have other creative interests and don't like being locked into a job.
Creative people can easily get burnt-out by doing the same thing every day.
Working on your own can be up and down. When I first started working freelance, I worked harder than I did when I was working for someone. Plus, I had no benefits, no paid vacations. People think when you're freelancing you can take off whenever you want, but that's not the case. I would get paid, then pay the bills, and I'd have no money left and no jobs coming in.