My hatch rate from shipped eggs has run from 0% all the way to 100%. It's always luck of the draw. I order and have them shipped because it does not make sense to waste gas to drive even up to an hour, when I could have them shipped. It's a risk I take, and I'm willing to take.
Some people suck at incubating, so I don't believe feedback on
eBay should be left on "hatch rate". I however, leave feedback based on "fertility" rate. It can sometimes be hard, and sometimes be easy to tell that eggs are fertilized or not. I know fertility can't be guaranteed either, but I sell hatching eggs and I test my fertility every 2 weeks just to be sure all is still in line, I also send extra eggs, because its no skin off my back, and postive experiences are important to me. I've been burned several times, some the fault of the seller, some out of anyone's control. I don't want people buying from me to have a bad experience. However, larger places can't keep up with people constantly saying "my eggs didn't hatch". The risk is what you take. I order live animals from larger, more established farms, and I buy hatching eggs from smaller farms (for the most part).
It sucks not having a good hatch rate, but you always have to automatically guess that you're only going to have a 50% hatch rate, ask the seller to pack well (I bubble wrap individually) it can be more expensive for shipping but when I ask for that if its not already provided I always have a better hatch. Also, ask when they last tested fertility!
eBay can be a sucky place to buy eggs, so really read the comments, and contact the seller, if they have a farm page, check the farm page! Be vigilant and don't give up.
Also, check out the Facebook page "good eggs and bad eggs" you can find feedback on several farms, and even ask about others experiences with sellers!