Pros
The company business is essentially outsourcing: staff aug, development services, sometimes even product design and consulting. Comparing to other outsourcing companies I'd definitely say EPAM is a good guy. Good culture, relatively fine salary (considering it's an outsource and you're on visa). The most important thing for me was the horizontal breadth of opportunities. There are so many different projects, domains, and customers that you can find pretty much anything you'd like to work with. Automotive, Healthcare, Fintech, Media & Entertainment, and so on. If you plan to grow into software architecture - here is your chance to get experience in many different domains.
Cons
Compensation often goes below the market average for the same skillset. May change after you obtain a Green Card. Depending on location in the US - the mentioned availability of project opportunities might vastly differ. Work/Life balance can suffer for Leads because you often have to manage a team of devs overseas.