Pros
You learn a lot. You work in small teams where you are an owner of your software. This means that you own everything, from writing the code to testing it to deploying and managing your fleet of machines. Depending on which team you are on, you will end up working with some cool technologies. This includes Amazon Web services (S3, EC2, SQS). You will most likely end up writing large-scale distributed systems. Like I said before, you will learn a lot. Depending on the team, you will not have support engineers or QA people to help handle operational issues and testing. You have to do everything yourself. This is a good thing, in that it gets you into the startup mindset.
Cons
You have to carry a pager to support your software. This means that you will be woken up in the middle of the night when you are on-call. Everything moves at glacial speeds. Projects that should take 1 or 2 months take 6 months. The bureaucracy is stifling, depending on which team you end up with. Any sort of project that requires work from multiple teams ends up progressing very slowly. Depending on the team, management can be very reluctant to approve of any clean-up work to improve legacy codebases. Pushing a new idea through is very difficult. I have tried doing this myself, only to be turned down. I have heard of many other cases where it takes up to 2 years to push a good idea through all the levels of management.