All in all the USPS does a pretty good job. Of the myriad of eggs I shipped this year only 1 shipment was delayed, and where it spent 2 weeks I can not imagine, because according to Mapquest the route could be driven in 10 hours. A word of warning to all egg shippers. Always pay for delivery conformation. There are buyers out there who will claim the eggs never arrived. Priority Mail really has no gaurantees as to how long the package will take to arrive, but typically at least in my case it is usually two days. Express Mail does give us some options for reimbursment if it is not deliverd on the time promised. For some of the more valuable eggs being shipped Express Mail is the way to go.
I would like to add that whether you have broken eggs or not is pretty much up to the person packing them.