FedEx Ground, for when it absolutely has to be there someday, maybe. :-)
Air shipment is no better. I had a next day FedEx package shipped on a Monday disappear until Friday. In this case they had choice of actually moving the package by air or land.
Overall I find UPS to be more reliable in my area. A few weeks ago a FedEx package that did not belong was dropped on my home doorstep. It was amazingly difficult to deal with that.
A lot depends on the local delivery person. In our business we were on a first name basis with the FedEx next day and the UPS drivers. If they had a critical package and passed us on the street, they’d give it to us on the spot, regardless of their schedule. Then we moved a few blocks, have a different set of drivers, and service has deteriorated significantly for both. Packages might be dropped on the steeps in a busy urban business district.
Fedex is a mess. I love the company Sweetwater (sweetwater.com). They have the very best customer service I’ve ever experienced (and they send candy!). However, they ship via Fedex. I recently bought a guitar from them, not a very expensive one, but it wasn’t a cheapie either. Having been screwed by Fedex before, I was on pins and needles watching the Fedex tracking screen. I was braced for a disaster of a crushed box and a cracked neck or body when I read the dreaded “Shipment exception Barcode label unreadable and replaced” in the travel history. Luckily, it arrived in pristine condition (a tribute to Sweetwater’s overzealous packing regimen, not anything Fedex did).
Fast forward a week, and I’m waiting on a (this time cheapie) bass for a gift to a budding young musician. What do I see again? “Shipment exception Barcode label unreadable and replaced” in the travel history. Hopefully I’m as lucky with this one as the last, but once again I’m braced for the worst.
Update:
FedEx delivered my package today as the agent promised. Package was still late but not as late as was indicated. Seems tracking on-line varies from what the agent sees even though the IVR says agents don’t have any additional information. You just can’t trust AI to tell the truth 
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