I agree with the above poster. I've been on a CGM for almost 5 years now because I have hypoglycemic unawareness in my sleep and have a history of night time seizures.
I started with the Medtronic one since I was on a Medtronic pump and it was integrated. I loved it, but was annoyed with the calibration errors and the annoying "out of range" alarms since I remove my pump when I swim and would keep it by the side of the pool (but that didn't seem to make any difference). The accuracy also seemed VERY off at times, and I hated that the sensors hurt so much! Despite all of these things, it was all I knew as far as CGMs so I stayed on it for a couple of years, until....
I discovered the Dexcom CGM after seeing a buddy use hers. The separate receiver (carrying around a 2nd device) seemed annoying to me at first, but I loved that the sensors seemed more comfortable, lasted longer (7 days as opposed to Medtronic's 4 days, AND you can usually get at least 10 days out of a Dexcom sensor) and perhaps best of all, the receiver doesn't go nuts when it's out of range - the alarms are completely customize-able!
I've been on the Dexcom CGM for the last 3 years or so and find all of the above to be great, PLUS it's WAY more accurate than Medtronic's. There's just no comparison. I don't mind the separate receiver - it's actually helpful because I velcro it to my handlebars when I'm on long rides and can see my BG in "real time" and take in carbs/give insulin accordingly.
Dexcom has come out with their G4 recently and it is WAY cooler looking - the transmitters are a little larger/thicker, but the receivers are very cool - they look like an iPod and come in cool colors. Plus, it's supposed to be up to 30% even MORE accurate. I can't wait to upgrade in April
