Vantaggi
Good work-life balance, not a lot pressure. Management is friendly and their are some fun people you get to work with. Decent benefits. Rewarding work getting to work with non-profits. If positioned right, you can get decent bonuses and stock grants to help offset lower salary.
Svantaggi
Mostly widely used framework is ancient in terms of tech stack. After years of paying for it the newer products are (finally) moving off it to more current technology stack. Pay is a little low. HQ Location is great (Charleston is gorgeous), if in Austin I would be shopping the market since it's a popular tech city. If you can get to working on some of the newer projects, you will be better off but even first glance at those seem to be following a weak architecture pattern.