Pros
as long as the business is going well, it is a great workplace. You can get new positions inside the company with a handshake agreement. They support learning and relatively good live work balance.
Cons
if the business turns bad, it becomes a horrible workplace. You can not get new positions inside the company in a different business group, because they promote silos and invisible boarders. Promotions are difficult, because you need more than just good work to qualify. once you are impacted by a workforce reduction and try to get back in, the HR department seems to put a "do not hire" tag on your account. the nature of the business is very Radio access network dependent. With bad strategy they managed to lose 2 out of 3 top tiers account in USA, and this is unlikely to change in the next couple of years.