FedEx has been the worst for me, historically, and lately has dropped substantially in quality. Lately they lie about making a delivery attempt, saying I wasn't there even on "no signature required" packages, which end up shelved until the next week. Recently I had an issue with food that was shipped overnight in a cold pack that received this treatment. USPS delivery has been great, and is the cheapest. Their tracking system is pretty wonky. I don't really pay much attention to UPS, which means that, for me at least, they're probably doing a good job, and I just don't notice. They're also more expensive than USPS.