Pros
Pretty fun job to have for a month or two. You get to be outside and stay active, and every driver I worked with was super chill and down to earth. Plus, just about every person you interact with is happy to see you. Was paid well and (for the most part) given plenty of hours. I voluntarily worked some Saturday shifts but I don't think we as helpers had any mandatory ones. None of the rumors I had heard about (such as paying a ridiculous amount in union fees) were true at the Asheville, NC location. The dress code requirements were simple and didn't require any extra purchases on my part. If you're an active, athletic person you'll find that it's not as physically draining or as hard on your body as you'd expect. If you're not in great shape, this job might help you fix that. No micromanaging and nobody breathing down your neck. You very rarely interact with anybody at UPS aside from the drivers.
Cons
Not enough trucks for peak season. Felt like we were understaffed or the facility was too small. A few of the routes I had to work with needed to use Budget trucks which is a huge hassle (at least it gets you more hours). Expect an atmosphere full of frustration during peak season. Not much of a con in my opinion, but some people might think it is: sometimes you don't know your schedule until the day of. However, that was made well-known to me before accepting the job, and in my case turned out to be more of the exception than the rule. The appearance guidelines (clean-shaven, no visible tattoos, etc.) are a bit silly but not a big deal for a temporary job.