Pros
If you have a job in this economy, be grateful. For union members the benefits are good. The work can be rewarding on its own merits. Boeing is spread all over the world - whatever kind of place you want to live, you can probably find a Boeing site there.
Cons
Defense has been providing most of the profits for years (read the Annual Reports) but Commercial thinks they're the only True Boeing; arrogant in the extreme. "Heritage Boeing" openly treats everybody else as second-class citizens even though they rely on "Heritage McDonnell Douglas" and the other "Heritage" companies to keep the Company solvent year after year. Boeing's share of the worldwide airliner market has been declining for a long time with no end in sight. Unions (factory and office) think nothing of paralyzing strikes at critical moments - remember JSF and 787? A company this big takes a long time to die, but this one can't keep going on as it has been.