Pros
AWS is a great place for self-motivated people who know how to broadcast and sell their successes. As a specialist SA, you get to work in the areas of tech that you enjoy and are good at, and get exposure to a wide range of people and companies. You can also take your job in many different directions, as people rarely tell you that you *cannot* work on something. This freedom comes at the expense of justifying your work with real data.
Cons
The freedom and ambiguity in a specialist role come at the price of needing to justify why you matter. One of the hardest things is watching people game the system and tell tall tales about how they've influenced the business, when in fact their contributions are huge embellishments at best and flat-out lies at worst. The constant writing, tracking your work, and finding data to back up your influence ears on you over time. Everyone at AWS has an angle since we are stack-ranked, so it's a dog-eat-dog environment. Once you accept that fact and learn how to work with people to win together, it takes some of the sting away...but still slowly grinds you down.