Pros
The 401k is incredible. You will find few companies that offer the diversity of investment opportunities, the growth potential of the funds and the match that CNA provides. You may b e lucky enough to get a solid individual manager, but mid level management is being stripped of all authority, so you will only be following orders as will your manager.
Cons
How much space do I have? The company in in pure upheaval. The most complete non-takeover takeover in history. The folks who were left out when Chubb was acquired by ACE are attempting to turn CNA in to Chubb. This is a management team that lacks creativity and imagination (apparently every meeting has to begin "Well, when we were at Chubb..."). Their style is top down - they give orders; input is not welcome. The systems are stunningly bad, including the primary underwriting system which runs on OS/2! Nothing better illustrates this management team's being in over their head than the decisions to include in the most recent layoff (more to come in the next few months) a person who was hired for a newly created role six weeks before the role was eliminated and - the very best - eliminating the role of a woman who is 7 months pregnant. And then having the person who made the decision say they did not know the person was pregnant - as if she wasn't showing. Enjoy that well-deserved lawsuit.