Personally the only reason I stayed for FedEx is because my boss is probably the greatest boss I have ever had.
It is hard work, but I don't mind that. It involves a lot of lifting heavy things, having product and shipping knowledge, and if you know graphic design and microsoft office like I do it's a plus.
Knowing how to work a computer is extremely important.
One of my main qualms is that I am paid very little for the amount of work that I do. I can barely scrape by and I go to university and live in a very wealthy area (not by choice, but more or less because I'm stuck here). I barely broke past two digits in pay, which isn't saying much.
The amount of work that I do, the type of work that I do, and how long I have to work are all the equivalent of someone working as an administrative assistant that's paid a lot more than me.
Plus side, FedEx does have super good benefits. They have blue cross blue shield health, signa dental and a 401K if you so desire.
It's retail so the customers are going to vary from really pleasant to unbearable, especially if you're working in the design section where everything has to be exactly as they want it (and I don't blame them- it's their own personal project).