Pros
There were some interesting and exciting conversations with guys who worked there for 15 to 20 years, and the 401k was so bad, that they literally lost some of their principle. That's not a typo. They never gained anything and lost some of their principle. This was during the good times.
So the "pro" part about it was listening to some of the guys come up with new and creative language to describe their disappointment.
Cons
At the end of the day, you know that you're just a number there. And since that is the case, you might as well get a job with a big corporation. At least with the big corporation, the benefits are much better.