I had an Amazon Prime 'specified day' item shown as 'out for delivery' with DPD on Friday 1st December. Having waited in all day I received a text c.14:45 advising that due to 'local circumstances' they would now be unable to deliver the parcel that day, but would instead deliver on Saturday 2nd December.
Whilst being a little surprised that they proposed to deliver on a Saturday I again waited in all day. No delivery, no update. The item was finally delivered on Monday 4th.
Messrs DPD misguidedly invited me to 'rate their performance' on TrustPilot and I awarded them a somewhat generous '1 Star' (the lowest rating available). I received an email a couple of days later apologising for their incompetence (my word not theirs) which they put down to 'a backlog following Black Friday' and stating that the text advising the item would be delivered on the Saturday was sent in error.
Still, Royal Mail have lost/delayed by over 2 weeks at least three items posted to me this year, so overall I'm unsure as to who is least efficient.