Pros
Decent pay and decent/tough hours depending on your team/manager and how you manage your responsibilities. The overall culture can be laid back, friendly, collegial at times. Not much upfront or direct feedback/criticism from coworkers and managers, though that can also be a con. Good food/benefits and employees are enjoying increased access to general training and learning opportunities.
Cons
Employees in the back office are for the most part, pleasant, diligent, and hard working, but are far from the most intelligent in the firm/industry and are easily some of the most lackluster people you will meet. Lack of passion and diversity in the back office (personality, pedigree, ethnicity, etc) creates an extremely mundane and demotivating environment. Senior directors are distant. Most mid level managers seem disinterested or dispirited. Most junior employees seem to be studying for the CFAs or making efforts to lateral to the front office / other firms. A good environment to be in if you're introverted and favor a predictable, routine life in a cubicle with good pay. However, the work itself is far from fulfilling, as it is mostly routine and uninteresting. Many roles will be phased out in the near future by automation as well as increased competition/desire to lower management fees.