Pros
Better work life balance than Big 4 with a more fun company culture than them as well from my understanding. Extremely flexible work hours. So long as you have a good manager and get your work done you can take long breaks during the day to go to the gym/etc. Vacation policy is unbeatable. There are some people who arrange for 4 day workweeks and take extended 4+ week vacations in the summer. Actual ability to make partner (if that’s your type of thing).
Cons
Busy season is often longer in duration than that of Big 4. Multiple clients means multiple client deadlines with draft deadlines in between. Big 4 may have more intense work hours on a given week, but CohnReznick seems to have 60 hour weeks that stretch from Mid-January through the end of April. Pay/Raises - these are going to be slightly less than Big 4, and a decent amount less than going in-house at a company.