Pros
In general nice people, you can have a career IF you are based in Wales and possibly Leatherhead. Some long term projects. Some interesting projects but the chances are you won't be on those and I'm never sure just how much CGI are involved or are just claiming the glory for someone else's work.
Cons
They don't take care of their staff. There's no career planning (although they say there is), training has to be fought for rather than being planned to help your career and there's no personnel management training. The annual review system is appalling, and I don't mean the program used to administer it. It has to be intended to demotivate people so they accept no pay rise or leave. It is utterly subjective and not fair. On the subject of pay rises - you can be acknowledged as doing a great job and making a real contribution but if you don't meet some arbitrary objectives, which might not be possible for you then you get marked down. Also they expect incredible performance which then becomes "meets expectations". Pay bears no relation to market rates or to your peers. Getting anything done internally is like pulling teeth. The staff in Bridgend still think they are working for Welsh Water and have a "Computer says no" attitude. Offices are variable - Ex Logica ones are quite nice but CGI doesn't believe in spending money on offices so the new offices are really horrible and not suitable for a professional organisation. Finally - the CGI and Logica systems and environments have barely been merged so there is still an us and them mentality at some levels and service desks for one operation to help people from the other organisation is hard.