Pros
Large company. Competitive benefits (there is a 401k match sometimes depending on overall performance). Competitive comp (if you happen to be in a viable territory). There are plenty of resources, if you know how to find them. Lots of company-specific training available, but doesn't really confer transferable skills or knowledge. Good technology.
Cons
No culture to speak of. Little to no upward mobility...it's a very large company, so there are a zillion people competing for the next rung on the ladder. Debt, Debt, Debt! Still paying off the Nortel acquisition. Draconian cost cutting. Good technology, but still trying emerge from the late 1990s, reinvent as a software/services company, blah, blah, blah etc. Have been looking to be acquired or go public since 2010, but too ugly to take to the dance. Actually, this place is a model of a cliche.