AT&T

Mostly good people, overall good benefits, and lots of challenging projects that are consumer-facing to millions of customers.

It's a large enterprise, so by the senior management level, you are definitely treated like a number. Lots of corporate mandatory training that is basically a useless time-waster. Also, in a salaried position, you are considered management and have to take classes every few years to cover unionized worker jobs in case of a strike (and potentially have to be called up to cover during a strike).

Health care coverage benefits were eroding over the years, with costs being shifted more and more to the employee.

You might think stability/job security would be a "pro" for a large telco company, but there are seismic shifts going on in the business sector and lots of "surplussing" (layoffs) happening all over the organization and lots of re-organizational churn.

Recent reversal of telecommuting policies.

You are not going to attract and maintain senior developer talent by micromanaging burn down rates daily during sprints and forcing people to always work from the office.