Senior management is very respectful and treat the employees as humans, but will not let you grow as a professional (probably because they feel threatened). Promotions are mostly based on seniority and not ability. So even if you are really good at what you do and qualified for the next level, you still have to wait in queue till the person who joined before you gets promoted first. Annual raises are a joke (they don't even cover inflation), and there are no performance bonuses. Not a lot of emphasis is given to professional development, or continuing education. They do not help with tuition, or provide any encouragement if you want to develop professionally on your own. Small town mentality means that they are very risk averse, and this shows in the decades old technology that they still use. Some people I worked with found it difficult to move horizontally into other areas within IT/IS, as such a move is not encouraged. In fact, some senior management will try to stifle such attempts.
Marshfield is a town of 20000 people or so, in the middle of farmland Wisconsin; make sure you are aware of that before you start at Marshfield Clinic. There is absolutely nothing to do there in terms of entertainment (unless you like to spend your evenings at hick country bars). There are no other significant towns around, the biggest city is Madison about 2 and a half hours away.