Had more bad experiences with USPS than anyone else myself. Best one for me would be UPS, any time I order from amazon (newegg too maybe, can't remember) it ships UPS and the thing always arrives at least a day before the earliest it says it should be here. Always. Every stinking time lol. Only ever had one problem with them when they delivered something of mine to a same-numbered trailer in a similar looking lot across the road. They didn't do much to help me find out where it went but I figured it out at the end of the day.
I'll say one thing though, post workers are really overworked, and that's probably why they didn't do too much to help me that one time.