I've had 2 wonderful experiences with DME and I'm looking forward to many more. Both times, I got to my resort as quickly as a car service or rental car would have gotten me there.
DME launched on May 5, 2005. It was supposed to end in the fall of 2006, but it was so successful in the eyes of guests and Disney suits alike that in April 2006 it was announced it would be around through at least the end of 2011.
It's served at least 5 million guests so far ... and maybe as many as 8 million in its appromately 1,000 days of service ... and almost all of them have been positive experiences. Have there been some minor delays such as OKW Lover experienced? Sure. Have there been a few isolated problems that were even bigger? Sure. But if you look at millions of car rentals, millions of taxi rides and millions of car service rides, there are also going to be some stories of delays and other problems.
There are no rampant or widespread problems with DME, just like there are no rampant or widespread problems with car services or rental car agencies.