Pros
The best thing about Epic is the campus - but you probably already know about that. There is a lot of challenging work (though whether it's interesting work is another story) and it's quite easy to change teams or roles if you decide to do so. The pay and the benefits are quite nice and you'll be able to save a lot more than if you worked in California.
Cons
If you go work here, be aware that you won't be helping your career at all. Yes, the main language in use is MUMPS, and yes, it is as horrible as you think. The technology stack is a nightmare and things like SVN and Visual Basic work against you rather than with you. Additionally, Epic uses a slew of custom-made internal tools which break on a weekly basis and bring your work to a halt. And your knowledge of these tools is completely useless after you leave. The company advertises itself as being casual but in reality people are constantly stressed about deadlines and code breaking in production scenarios. A lot of people ended up working longer and longer hours so that they don't fall behind. The constant breakage of internal tools didn't help get our work done in time.