Pros
Top brands that look amazing on your résumé. Pay is decent. Little oversight: your weird idea can make it to production within a day. Designers and editors care deeply about their work and how it's presented.
Cons
This company is large enough to take more responsibility in what they're putting out there. Certain brands operate in their own technological fiefdoms, where things like build tools, tests, code quality, and many other important parts of modern web development, are left solely to the discretion of the ranking member of the team. The political corporate reality of this lack of oversight results in situations where you, as someone who strives for a more sound codebase, can feel ostracized for rocking the boat—rather than empowered to contribute something meaningful to the product at large. Discussions are shut down and shade is publicly thrown, rather than a conversation on the merits on either approach.