I have a Subaru Outback with DRLs, and I love them. I never forget to turn my lights off, since they shut off when I turn off my car, and when I need them, they are always there. I also like them on other cars, especially around dusk, when DRLs make cars more visible.

You've just alluded to the reason why I think that they are crap. People rely on DRL when they really should turn on their lights. Ok, so DRL may help an oncoming vehicle see you, or for a pedestrian to see that you are coming. But they wont do anything for the car that's speeding behind you in the rain. DRL are front facing only. I also have a suspicion that people would be more likely to turn on their lights earlier if they didn't have DRL.

It's a false sense of security.