Pros
Pay and benefits are excellent. If healthcare is your passion, you will also learn a ton about how the industry operates. Epic's reputation as a grind machine in the Madison area also means that former employees can find new jobs quickly, because they have proven they can work hard.
Cons
Management runs on "feedback", which means whatever your coworkers and occasionally customers (but usually your coworkers) say about you determines your growth in the company. Given that very few Epic employees had substantial careers anywhere else prior to Epic, and that the Epic burnout rate is high with employees rarely staying more than 5 years (or even 3), the feedback system has resulted in a management structure with very little diversity of thinking. Put simply, no one knows any better. So, you better tow the company line and kiss up. If a coworker is having a bad 18-hour work day and in their 1 year of work experience does not like an email you wrote, they might complain to your team lead, damaging your career as a consequence.