Avantages
Your colleagues are decent people, and make coming back to work in the New Year less unpleasant. Camaraderie, support from colleagues is excellent. You are wanting to avoid Competitors who treat their people badly; amazing as it sometimes seemed, I've heard our Competitors are even worse on delivery than FS.
Inconvénients
Most projects go pear-shaped after a year and then everyone is in fire-fighting mode; a lot of people have made good careers at trouble-shooting. This is unfortunate, as things should go right first time. I personally have been on a big project from the start and seen things unravelling in front of my eyes. No-one seemed to know what to do. Also, little Private Sector work means working at the pace of the Public Sector. Civil Servants are nice folk, but hamstrung by culture and political imperatives.