I have owned the Seven Plus since September 2010. Owning this product has been life changing. I actually bought some shares in December 2010 after realizing this company had stock that traded on the market. Had I known sooner, I would have likely bought in sooner.
My last two A1C readings since I bought the Seven Plus have both been improvements; 6.7 to 6.5 to 6.3. This after my doctor telling me its unlikely that my A1C could get much better.....The sensor is fairly accurate, as long as it stays calibrated. The trend for accuracy seems to be that the higher your blood sugar, the more the discrepancy. The "graph trending" feature (rise/fall rate) on the monitor is extremely accurate.
I've been a type-I diabetic for 30 of the 32 years of my life and have been in tune with many of the technological advances over the past three decades. There was a time when finger stick readings were done once a day as the standard -- now 4+ per day is the standard. I would expect that the Seven Plus, or a similar product, will be the "standard" for sugar monitoring in the next couple years. While the replacement sensors are slightly cost prohibitive before I meet my deductible, its not totally unreasonable.
One other feature that makes this an incredible product is the data storage and the ability to use a PC to synthesize the data. You can track up to three months of data, where the data entries are the five minute sugar readings. Data is customizable into graphs, pie charts, bar graphs, whatever.
Whatever company corners the market on continuous glucose monitoring systems will be raking it in. Big time. I'm betting Dexcom.