I had to register and give my two cents. For benefit information talk to your hr. I do make more money, than I would as a loader. If you're single, with no dependents, you won't have to pay for insurance. Also, for some reason we just started getting payed once a week.
Everyone else made good points, but they missed what I think is the two major differences.
Don't do it for the money, my pick-offs make more money than me. The money will come if you hang around ups long enough. That said, if you need the money, I get payed 27.5 hours a week. Most weeks, I get around three hours over time.
You need to think about all the people you work with, do you really want to manage them? You're the best there is in your building, everyone that works for you won't be as good. Get a misload sheet for your building , your pt sup has one he's going to trash anyway. Pick five or six names off at random. Those will be the people that work for you. You'll be expected to fix their problems.
I don't know if your belt runs well or not, but not expect to stay there if you become a pt sup. Pick the one that always screwed up and expect to go there.
I like my job, I don't kiss my friend/t's butt and I don't expect to move to friend/t management. Most p/t sups don't seem to like there job. Expect to take the blame for other people problems, explaining to a district manager how a loader misloaded x number of packages isn't fun.
What it comes down to is, you go to work, get in a trailer and load packages all shift. You don't have to think about it that much, when the sort go down you go home. I got to work about 45min before you do, I get bitched at for whatever packages were misloaded, not scanned, damages that work loaded, belt stops, ect... Then I spend my night juggling paperwork, loaders, trailers, pick-offs, scaners, ects. At the end of the night I'm responsable for anything that went wrong.
I'm not saying you shouldn't becoume a pt sup. I like my job. I'd go to the dark side if I had it to to all over again, but it's not all green grass like it looks from the other side of the fence.