Their delivery service is frustrating. It seems to be the norm, and accepted, that drivers will mark packages delivered a full 24 hours ahead of time and do the delivery the next day, presumably to meet delivery requirements.

I've also had these individuals basically solicit me for a tip, recounting how they're underpaid, etc.

I really don't like this move to try to uber-ify package delivery. UPS/FedEx have their bad moments, but at least I don't have to worry that the employees are under too much duress to deliver, or are on the edge of unreasonably compensated.