Pros
Flexibility in work arrangements. ( -although co-locations is now being enforced) No Big brother culture. ( -although that's changing with Continuous Improvement/LEAN introduction) Job security.
Cons
Huge outsourcing of techincal work to offshore contractors during mid-2000 has completely decimated the in-house knowledge and expertise. A lot of very good/world class engineers have left BT - glass ceiling exists for technical staff. Line management completely dominated by HR, accountants, and spin merchants. The messengers get rewarded I would say disproprionately more at the expense of the actual doers than for other large organisations. The actual time spent recordings what you do is full of glaring gaps. There are constant management initiatives and a lot of JFDIs from the poorer managers that do add to your workstack but are hidden/buried into existing project codes.