Pros
If you become a "blue badge" the benefits are pretty decent. You get excellent medical/dental/vision for an affordable cost, and you receive RSUs (Restricted stock units) which vest after 2.5+ years. You also become entitled to a monthly performance bonus (based on how the building as a whole performed) and if you work for AmazonFresh, you will receive extra money from a tips pool.
Cons
The working environment is pretty harsh. All direct functions (picking, packing, shipping, etc.) have production rates which are closely monitored by a computer system. If you don't make rate, the computer will automatically write you up (3 write ups and you're gone). Most managers on site are inexperienced and micromanage employees. Picking is the most common function, and your average picker speed-walks distances between 10 to 20 miles per shift. So the job is extremely physically demanding. The base pay is OK considering the industry, but for the amount of work you do you'll quickly feel like you're not being payed what you're worth. Also, don't expect to be promoted, as you'll be always competing with every other employee, and Amazon does not promote based on tenure-ship.