Pros: goodies available on breaks, locker space, free holiday clothing for change in uniform
Cons: short breaks, seasonal, no outside breaks on night shift
There is a lot of lifting as a stock crew member, so if you have a bad back, heart, knees, etc. this is likely not the position for you. Staff are hard on you, especially if you're new, and especially if you're young. Some staff will be harder on you than others.
If this will be your first job, it will work nicely. You may not enjoy how tough they are on you, but it will definitely help you with keeping a good mindset for future jobs.