Pros
In general good benefits (pension, work from home, flexible hours, work life balance etc). If you are lucky to be in a good (potentially growing) area of the business you will have an O.K. work experience, very good exposure into IT within various sectors e.g. energy, finance, retail and public sector. This exposure can without a doubt give you the needed experience to bolster your CV to move upwards in your career (probably not internally though).
Cons
No social events e.g. no Christmas party and no team gatherings. A lot of people work from home leaving some people feeling isolated, 99% of meetings will be over Skype. No travel to client site unless absolutely required. Bad press in the media due to loss of contracts and redundancies. Real estate consolidation meaning some people cannot go into a local office even if they wanted to. Disconnected workforce from management to ground level employees. No scheme for graduates, interns or apprentices, all thrown onto accounts and made billable to a client for maximised return on investment - this however can be a good thing for exposure on CV.