Pros
Work from home option is nice, although all the offices are ghost towns now. Can be a great place to work out of college, it's possible to move up to a middle management position fairly quickly. Take it as a pro or a con, but many at the company have agreed, anyone who is at Epsilon past five years is still here for the lifestyle (i.e. once you get to a certain level the amount of work is minimal, the pay is ok, and you have the flexibility in schedule that allows you to focus on your life outside of work). All of that is great, but when the majority of middle and senior leadership are doing it, it leads to inefficiency and frustration for those that have to pick up the slack. As the saying goes, "Somebody's gotta make the doughnuts". Just don't be the doughnut maker here, and you'll be fine.
Cons
Constantly trying to position itself as a product company, but there are no products to sell, besides the email platform. Offshoring everything to India, but without a very good working model for those of us who are onshore. Read above, work/life balance can be fantastic (i.e, a lot more life than work) for those in upper positions, but can really suck for the worker bees. Pay attention to the titles, if you are "Sr" something, you'll probably enjoy it.