I actively avoid sites that use them, even if I have to pay more.
When I lived with my parents (on a farm) we had a driveway sensor, so any vehicle that came through the gate and down the drive would trigger a ringer in the front passage way. It could be turned off, but if I knew I had a package coming / was alone in the house I'd always put it on.
I waited ALL day for them to arrive, and nothing! I waited for at least an hour basically sitting by the front window, generally mooching around expecting the guy to pull up. No chance.
As mentioned, if you didn't pay good money for a next-day delivery it wouldn't be so bad, but the worst part was when I rung they a) said they'd carded me b) lied about the colour of the front door, when challenged about the card c) backtracked when I told them the front door has no letterbox opening.
When it did arrive (£2000 worth of new PC & monitor), it looked like it'd been kicked all the way from Stoke, to my house.. So I refused delivery
If the drivers can't make the drops they need to grow a backbone and tell management, who can then inform the affected customers.
Only other courier I've had issue with is Yodel/HDNL. Royal Mail are great here, so I actually prefer special delivery to a crap (see City Link, Yodel) courier if I can get away with it.