I think it really depends on where you live. FedEx here is top notch with earlier delivery times.
FedEx > UPS > USPS
USPS once claimed they left a package at my door, they even sent the mail man back to my house and he pointed out to me exactly where he left it. About 5 mins after he left he returned, then hands me my package. I asked him where he found it, he claimed he got it out of my mailbox. Trouble is, my mailbox is locked and he doesn't have a key. No way he took that out of my box through the mail slot. Sounded shady to me.
above isn't my only FedEx horror story. when i got my iPhone 4S, the FedEx driver left the package on my front step despite it requiring a signature. when i got the alert that it was delivered i called Customer Service and filed a complaint with a request for it to be picked up and held at the local hub. i got a call back from the hub manager stating that they don't re-pick up packages once they have been officially delivery and advised that i have a neighbor hold onto the package for me. i reminded her that the package required a signature and the driver ignored that requirement and now FedEx will be liable if it gets stolen. she said "well we'll see if it gets stolen then". i said "no we won't, you will send your driver back now to pick it up and hold it" . she said "i'll send someone over when there is an available truck".
the package sat there for 2 days before a FedEx truck picked it up again.
then another time when i bought a laptop cooling fan, the box was a large flat thin package. the FedEx driver didn't even place the package on my step. i saw him through my living room window, walk onto my lawn (didn't even bother to walk on the walkway) and threw the package like a frisbee right into the bushes on the left side of my front door. then he ran back to his truck and drove off.
this is what FedEx does, over and over again.
UPS has never caused any similar problem and has been absolutely great. i have had my fair share of incidents with the USPS, but all you need to do is be friendly with your local post office and mailman and you'd be surprised how helpful they can be in a case of package mishandling or something of that nature. besides, USPS Priority Mail flat-rate is the best value your money can buy from a shipping perspective. it's amazing what i can fit into a legal flat rate envelope and send it from Pennsylvania to California in 2 1/2 business days for $5.30