Pros
I've enjoyed working at Amazon, it's fast paced, you have fantastic levels of ownership, the attitude is can do and you are expected to drive change and improvement, colleagues are smart and stimulating. The company continues to grow a rapid rate and that creates lots of opportunities internally (e.g. I'm on my 3rd role here in 3.5 years), there are usually secret projects going on building out the next product. The move into Central London has also been very good socially and for mixing with colleagues, previously in Slough there were very limited opportunities to go for a meal or a drink after work and that really put a brake on say Friday evening drinks.
Kontras
People move roles rapidly (18months to 2 years is typical) and between functions/teams, which is great for development but also means the company suffers from chronic people gaps and knowledge gaps on things like: what happened last year, how processes should operate. Culture does not suit everyone. It's cerebral and you have to be able to operate in what the company calls Dive Deep mode: going into detail, asking why repeatedly, finding root cause for issues, knowing all your metrics (and we have a lot of them!). People whose preferred mode is influencing and inspiring people whilst floating above the detail will struggle. Travel expense policies are stingy, e.g. economy class for long haul flights.