AWS is a great company to work for, especially if you are looking to cut your teeth on novel, never-before-seen issues. This is something I personally valued as an attorney, since I chaffed at the notion of relitigating (not literally) the same questions repeatedly. If you like to learn and be curious, this is a good company for you.
The only downside is, sometimes, managers don't always prioritize professional growth. Thus when people succeed and want to challenge themselves further, there isn't always a clear pathway up or forward, so it feels like a lot of lateral movement.
Good place to work overall, unfortunately my team got restructured during the last couple of months of my contract with the company making it difficult to get hired on. This also coincided with a new manager who micro manged and wound up at times costing productivity. This unlike the standard Amazon manager or employee, and should be taken as an unfortunate and unique circumstance that is not conducive to the overall Amazon workplace environment.
I have worked at Amazon for my summer internship. The experience is quite challenging, especially if you have no prior work experience. Since, I worked in an intern capacity I can't say much about what it would be like as a full-time developer. Also, it depends on where you are placed (ORG) and team. Manager and mentor also play a large part in your internship experience as they define the work culture.