Pros

Great job security, great benefits. Unless you have the IQ of a 5-year old you will never get fired from that place. The health insurance is very good, they will match up to 6% of your 401K contributions dollar for dollar, vested immediately. You also get over $200/month in free services. Depending on where you end up the work atmosphere may be good too and there are a lot of good people to work with. It may be a good place to start your career as long as you don't stay there for too long.

Cons

The state of organization and management is beyond poor. It's such a big company that the left arm does not know what the right arm is doing. No matter what project you are working on, someone else somewhere in Comcast is working on a similar task, so you always end up competing internally against another group. There are always internal feuds going on throughout all levels of management with different branches of the organization fighting for control. Major re-orgs happen once a year, which only adds to the chaos.
No matter what you may think, Comcast is not a software company, and not even an engineering company. They are an operations company first and foremost. This trait is something you see throughout the cable industry because most people who work there came from support and operations and have little to no experience with engineering, architecture, and software projects. Because of the operations mentality the company has a very rigid culture of blame and shifting responsibility. When there is a problem, the first question is always not "how do we fix it?" but rather "who can we blame for this?" Additionally, because they are an operations-minded shop everyone is very resistive to change and it usually takes weeks to agree on anything or get anything done. Much of the management at this company make your average DBA look like a risk-taker.
The pay was crap, but I also know people who made good money there. The one common thing was that once you accept a job you don't get good raises or promotions, other than nominal title changes, and even those are hard to come by. So if you take a job make sure you ask for good money upfront and don't believe any promises of them "taking care of you next year."

Advice to Senior Management

1. Get your sh.t together, develop a comprehensive strategy, and stick to it. Stop pitting people and groups against each other.
2. Learn how to run your engineering branch like a technology company, not a telecom of the old.
2a. Hint: people with production support background do not make good engineers or developers because they will resist innovation to the death.
2b. Another hint: breeding project managers endlessly does not get projects done - it only institutes more bureaucracy.
3. Stop the culture of blaming, pointing fingers, and evading responsibility. These things typically originate at the C-level and spread downward.