Pros
Comcast can be surprisingly flexible. Engineering is valued and people willing to take initiative and responsibility are generally appreciated/rewarded. There is a strong culture supporting balancing life with work. Sacrifice is also widely recognized. Additionally, there is a strong cultural bias towards hiring/retaining smart, capable people; sometimes to a fault! All the while, there is a desire to maintain good "cultural fits" amongst the engineers.
Cons
Mainly the traditional "big company" type of pitfalls: institutionalized inertia; broad communication issues up and down the verticals, etc. Comcast also has to transcend a certain amount of bias towards it's traditional revenue streams and face changing customer needs and demographics.