Pros
Job security - given how much trouble they have getting hiring requisitions posted and filled, there is very little worry about stability. Freedom - very little oversight on where/how you do your job, provided you're doing it. Working remote is very common for PMs.
Cons
Bare bones - most offices are strapped for resources. Sales is directed to sell at all costs, but most times there is not enough Operations to back it up. Uneven distribution of talent/resources to offices - if you're in one of the "good" offices such as Chicago or Tampa, you'll have everything you need to succeed. The rest of us? Not so much. Benefits - Health is pretty bad. 401k match is a mystery every year, and the percent is not that great even when they do it. PTO /Holiday is pretty skimpy, especially for the hourly people like techs.