I shipped a small one pound package early on a Saturday morning and was told it would arrive on Friday. It didn't arrive by then, of course.
Saturday came and still no package.
When I checked it with their tracking number I found out that it didn't even ship until Monday, and no other information was available. FedEx sends email updates on your package's progress. UPS tracking doesn't really track anything.
I'll use the Post Office before I use UPS again.
I would recommend that if you want a domestic delivery before two weeks passes, don't use UPS ground.