Pros
You'll get some decent brands to put on your resume/portfolio, that's about it. Of course, they've lost so many clients that most of the brands are no longer household names.
Cons
"We are not a tech company" is a direct quote from the CEO. Stay away if you do web development, QA, DevOps or anything in the tech field, you will not further your career at all or get opportunities to learn. All this company cares about is the bottom line. Get ready to justify every minute you log on your timesheet. I regularly spent 15 minutes arguing with account people over the 15 minutes of work I did on their accounts. Work/life balance? Hopefully, you don't have a life, because you will be expected to work after hours and on weekends. If you think their unlimited PTO policy will make up for that, think again. You will get in trouble if you take more than 15 days, even if you worked more than 15 weekends that year (true story). Upper management does not care about the people who work hard for them, which is why their turnover rate is so high and why the CEO made retention a goal for 2019. My experience there was awful and I very much regret not leaving sooner.