1. The entire accounting and tax environment that I experienced can best be described by two words: chaotic mess. At any given time in any given group, a majority of people are not going to know what is going on (See point 3 for lack of training). There are constant fire drills, and disorganization causes even simpler tasks to take 5 times as long as they should.
2. Turnover is through the roof (for good reason). Accounting and tax positions below the controller/manager level are just a continuous revolving door of 20-somethings straight out of college. This only exacerbates the already chaotic environment, and hurts morale.
3. Training is non-existent, which is extremely frustrating given the complexity of the work you will be expected to do. Much of it involves Koch specific processes that there is no way you could have even learned in school. This is a recipe for a nightmare situation if your direct supervisor doesn't have a solid understanding of the work you're doing (which is likely to happen since people are constantly changing roles). Hiring tax professionals directly out of college is a relatively new strategy for Koch, and they are clearly not doing an effective job with it. Their CPA perks are a joke compared to public accounting firms as well.
4. Horrible work/life balance. The tax department likes to market itself as an alternative to the infamous Big 4 busy seasons, saying that work is more spread out throughout the year. The reality is that you will basically be in busy season year-round due to the constant entity restructuring transactions that take place.
5. Much of their technology is severely outdated, although to their credit they do seem to be working on this.
6. The atmosphere is extremely cultish. Be prepared to spend hours upon hours pretending that the points made in Charles Koch's books are profound and enlightening. This is minor, but it's definitely creepy.