Pros
The pay is great compared with other industries, management seem perfectly willing to send employees on training courses and the teams you work in are usually smart, motivated and on top of what they do. If you work hard and make sure that your managers recognise it then they will usually do a lot to help you go further. Typically they're more than willing to handover more senior duties to you if you've proven yourself, which helps a lot when it comes to salary reviews. At least in the IT area I work most people tend to work 9-6pm so the hours are quite good but that may be due to it being a down turn and hence lack of motivation to work for a bonus. However, hours can vary wildly and really depend on the team and business function you are supporting.
Cons
As with all companies there is a lot of protective red tape which is often cumbersome and restraining, this can be very frustrating given that most employees see this as more than just a job and are actively trying to improve the way things work. Although the culture is generally very friendly, you'll find its common to sit near someone and not even know their name.