Yes I have done twice. I got a nine out of eleven hatch first time. The one egg that dies was my fault though. The second hatch wasn't so good. Only nine out of 23 hatched. I read every where to expect a fifty percent hatch rate on shipped eggs.
Despite wildly fluctuating temps & humidity, I had great luck with my ebay eggs. I bought 16 eggs, and hatched 18.
Sellers typically include extras so that even if a couple are damaged in shipping you'll still end up with as many as you paid for. Something to check with them about, though, so you'll know how many to order!
I've had good and bad luck with buying hatching eggs off of eBay. Mostly good luck. I'd take the plunge. Especially if the breed I'm seeking isn't anywhere near my area for me to purchase. It all depends on how they are handled during shipping and how old the eggs were when the sellers shipped them. Most ship fresh, others may not... It's always a gamble.
You aren't really buying eggs from eBay. You are buying eggs from individual people and some are going to be really good and a few people are going to be crooks.
There are several breeders who post on BYC who sell on eBay. So those would be safe to buy from. Also, you can try asking here if anyone has had experience with the seller you are considering, Usually, you have a couple of days to decide whether or not to bid.
Also, if you look at the stickies at the top of the ducks section, you will see a waterfowl breeder's directory