Pros
On the upside I would put the relative freedom that you have in selecting the projects you would like to work on, and the approach that you will follow in tackling them. Also there is a good level of respect and humility in the work place. People are kind and helpful.
Cons
- Management is basically comprised of ex-researches, with poor management skills. - Although there is an effort to connect Bell Labs with the real word challenges faced in the market, this effort unfortunately falls short. - An unbelievable amount of time is spent in presentation and demo preparations, and relative little in solving the problem at hand. The more buzzwords you put on your presentations, the better. Often the presentations are misleading, because they make claims that don't hold, or omit to mention important limitations. - There is a large amount of duplication of work across teams, due to lack of communication, or simply because different managers want a piece of the pie of the next Big Thing (e.g. analytics, ML, Cloud) - Compensation is average, and it increases in-pace (that is slowly) with the industry average. In other words, if you are a smart engineer/researcher, you are better off in another company.