If you have the choice do NOT do preload supe. As others have said, the hub sorts (especially night) are more laid back. The preload is brutal sometimes. I'm used to it, I don't really regret it other than the fact I miss loading. My drivers weren't happy when they saw I was a supe. Though since I trained a decent replacement they've since become ok with the idea haha.
For some reason the preload shift seems to be held to a higher standard than the others, we also get the least amount of recognition in return (management and hourly alike).
This is my second year as a PT Supe (4+ yrs @ UPS overall) and while the stupid ideas that you know won't work the second you hear them are still abound, the job never changes. Numbers numbers numbers....it's all you'll hear, its all they want (most of them). They don't care if your father died or your dog ran away, get results or else. The fact that the one barking the order could do little to no better than you means nothing. This includes mechanical failure, where our sort aisle supes get yelled at for out of syncs because the printers don't go fast enough (this is my personal favorite) to keep up with rate of flow our manager dictates. The equipment is simply not capable of meeting this number, yet the supe gets in trouble anyway...I'm dead serious you couldn't make this crap up.
Someone also said it depends on your FT supe. This I also agree with and I am in decent shape because I get along with mine very well, but your mileage may vary.
Do I regret it? no not really, but there are times I wish I still loaded. If you decide to go for it... Grow thick skin, be fair but firm and remember those people humping packages for you AREN'T numbers, but human beings doing the job you did just a short time ago. That last part brings me to probably the most important thing..above all else remember where you came from, even if those above you don't.