Depends upon the warehouse .....some are small new and local sorting loading delivery trucks most packages are light small and scanning tracking bar codes is by hand wand or past stationary scanners onto conveyor belts......workers are expected to work fast and efficiently early morning hours or clean out trucks in the evening for the next morning's loads.....bigger warehouses have bulk stock to fill customer orders and there is huge pressure to work perfectly and quickly packing inventory safely.....UPS IS UNION WORK so you are not likely to lose your job at whim or sexually harassed at an old company AMAZON IS NEW and out for blood..
.you might work side by side with an infected person UPS is working hard to keep shipping customers factory direct
....Amazon is buying out factories and now owns Whole Foods
.....in short your current job is easier and secure AMAZON may be harder and very less secure high turnover in hiring & firing

I have no experience or knowledge. However I did just yesterday watch an in-depth FrontLine episode on UTube. Did not sway me either way.

I've been buying from Amazon since 2000....they have really evolved. Would I stop over mistreating of workers? Environmental issues? Well, I am in the residential construction business in the US of A ....I can't imagine it being any worse.

If you are not vested in your present position, and won't be out any benefits, give it a shot. Why not? Even one of the Amazon execs interviewed in the FrontLine episode suggested taking the job, take full advantage of their benefits, like free education and then quit in a couple of years. Improve your education and skills....and move on.

If you want to know without actually working in one, read the section on Amazon in the book On the Clock by Emily Guensdelsberger. (The entire book is excellent) She captures the reality of what it is like in vivid detail.

Don't join them, at least not in a warehouse role. You are nothing more than an extension of a machine. They will use you up and spit you out. If it is just a short term gig for you it might be OK, but long term? No.

I have a grandson that look works in one in Minneapolis.

He does not complain about working conditions. My son seems to think he likes it partially because he's a gamer and their training program uses the same kind of promps that online games use. I'm pretty sure that means you are placed in competition with other workers for getting things done rapidly.