Pros
I have been working at Rational Enterprise for a year. From my experience here, most developers are helpful, innovative and friendly. I have learned new technologies and feel like my overall knowledge of software development has increased. Supervisors have monthly meetings with each developer solely to make sure they have everything they need to be a good employee. Senior developers are smart, insightful and provide mentor-ship to new/junior developers. My experience here has been fantastic. I highly recommend.
Cons
You have to be able to produce good work on your own. Meaning that, if you need strict structure and management in order to be a productive developer then you will not get the most out of working here. You need to be self-motivated, willing to learn and apply yourself.