Pros
The team I'm currently in is awesome (I work in something related to the Amazon Echo). My manager is great at providing guidance without micromanaging. And everyone all the way up to the SVP is friendly and collaborative. We work on cool new things and have a lot of opportunity for growth. The work is challenging, but not overwhelming to the point of destroying work/life balance. Overall my experience working at Echo/Alexa is awesome.
Cons
I've previously worked in a different team at Amazon, so I know my current experience isn't consistent across the company. You need to make sure you find a great team and a great manager. That makes all the difference in the world. Also, Amazon doesn't offer as many perks as Google or Facebook (no free meals, no free parking) so that's a small con, but it's just something you need to take into account when comparing your total compensation.