Vantaggi
A lot of talented people working hard to provide a good service to their customers. Sheer size means a lot of opportunities for promotion and travel. A competent and formal HR process for any complaints and development. You will get paid on-time and will get reasonable benefits and vacation. With effort you should be able to find someone in the company that can answer any question and help with any query. The right employee with stamina should go far.
Svantaggi
The talented people are let down by poor mid-level management with no real vision. Plenty of opportunities for promotion because too many good staff simply gave up and left or got arbitrarily laid off. Junior sales is a rotating door and too much account management is done "by the numbers" rather than with a view to real account development. There is a problem with mid-level managers not being held accountable inline with company ethics standards in the same way as lower-level staff are. Development and training are subject to random cost constraints and management whims. You will get paid, but it probably will be industry average or lower wages.