This article appeared in the August 29, 2006 edition of the New York Times, by Mr. Dan Hurley. Mr. Hurley, a diabetic for 30 years, recounted several episodes of severe hypoglycemia, including a recent episode, in which he almost didn't wake up. The article focuses mainly on the advantages of catching lows. Here's a snippet from the article and the link to it:
The Beep of the Sensor, the Thrill of Control - New York Times: "The main problem was that the sensor was simply not as accurate as a blood-glucose tester. MiniMed’s studies show the sensor’s accuracy can be off by as much as 18 percent. Another sensor, just approved by the F.D.A. and made by DexCom, is said by some researchers to be a bit more accurate, as is a third device, from Abbot, which has not yet been approved. But none are as accurate as a standard blood-sugar test."