I have always had problems with metal earrings. Silver tarnishes, the hypo-allergenic coating washes off, etc. With regular earrings, I ended up having to buy a new, more costly set with in a few months of each other because of these reasons. I have very high-maintenance skin... any little thing can cause an allergic reaction. That said, where have these earrings been all my life?! They are just perfect. They will never tarnish and they were made hypo-allergenic, so there's nothing to wash off. The backings to secure the posts fit snugly on there and I don't have to be afraid of losing them. Even if I did, the set comes with enough replacements for every earring you get. The size of the earrings are exactly what I prefer.
I've attached a short video so you can see just what you're getting!
Update 12/1/11: Be aware that the plastic backings to secure the studs in place will harden and slightly shrink if you wear them in the shower repeatedly. For the price it's not such a big deal to go back and order another set to replace them, but I've had to throw away 6 already and it might be something that irritates you in the future.