With couriers you are at the mercy of the final delivery agent. Often this can be a self employed "Man with a Van". Even with companies that use their own staff you are still at the mercy of the staff in the local depot. Whilst I can'r fault Podcast Bobs service, the company he uses to deliver seem to have problems actually delivering to us. Can't remember which courier it is ATM, but several times they have claimed to try and deliver stuff (not just from Bob) and left a note because no one was in, when they haven't been anywhere near us. I suspect that we are near the end of their run and if it's late they just return to base.
Bob says he chose them because he found them to be the most reliable, which they probably are for most people. However, the staff in our local depot are a waste of space.