Pros
Some of the people I worked with there are absolutely fantastic. It's difficult to see such hard workers being ground to dust though.
Cons
Senior management is incredibly distant from workforce (barring a married director having the most blatant affair with a subordinate - I am gobsmacked to hear it's still going on!). I had the unfortunate experience of having a narcissistic sycophant for a manager but not to worry, the middle managers are not all like that. The (good) middle managers are just as frustrated as the employees. Managers are trained not to question and to only give out "positive" messages for whatever new American workplace trending schlock is imposed - these trends used to change every 3 months or so and in the build up to the employee engagement survey, the poor sods (managers) would need to clap hands and tap feet for "company fun days" or "an ice cream. If you are a hard worker, you will be worked into the ground with little recognition. I'd see the same people with me working early in the mornings into late at night. Sure, you can get promoted however promotion is based on 5% increase based on your previous role's salary. I later realised I was earning around 35% less than my peers. Also, there is a lot of restructuring, redundancies (really badly managed redundancies recently I'm told), emphasis on offshoring, an expenses freeze that has stretched into years, and I hear it's unlikely there'll be a bonus (again) this year. My advice to any prospective employees... If you value your sanity, work life balance, and your soul, do NOT work at ADP Chertsey!