Pros
Flexible working options, can work from home when needed and no fuss leaving the office for appointments, etc. Site work can vary depending on location and current project work, sites tend to be local to your area though. Good benefits like health care plans, financial advice, cycle to work schemes and much more. Friendly working environment and you are left to get on with your work without constant supervision, but plenty of people ready to help if needed. Being part of a larger company can provide lots of work variation and training opportunities.
Cons
Maybe not the most competitive salary. Being part of a larger company can mean getting certain things approved take longer and can feel like your a small cog in a big wheel at times (project dependant). Not much hands on with hardware, primarily software and documentation work (personal preference, this could be a pro for others). The IT infrastructure is strict which can make doing your job more restrictive at times compared to smaller companies.