I'm rather surprised no one's responded to this already. In any case, I'm type 1 as well, and just received my CGM (Dexcom G4 Platinum) on Friday. I'm not certain about other brands or models, but with the Dexcom G4, you have to take 2 finger sticks 2 hours after you get it installed (it takes time to warm up apparently), and then the meter will remind you every 12 hours after that. So far, the farthest off the CGM has been compared to the finger stick is about ~20 (105 on the CGM, 126 on the meter). Most of them have been a difference of 10 or less. As far as how to calibrate it, the meter has an option to enter the BG level from your meter, and it takes care of it from there. Just select the BG level and the time the fingerstick was done (it does need to be within 5 minutes of doing it; no going back and fudging with numbers).
The transmitter being in my stomach hasn't bothered me in the slightest, except for it being a little itchy. I have mine placed just diagonally above my hip bone by about 2-3". Inserting it was about as painful as a normal insulin shot.
The CGM is vastly more convenient, and less painful than other meters I've used. Between only having to stab your fingers twice a day (you can do it more often if you're concerned about calibrating, or whether the numbers are off. In fact, they reccommend you still use a finger stick before delivering any insulin to confirm the numbers), and the CGM is smaller than the other meters I've used that keep track of carbs and insulin like it does. The Dexcom G4 actually comes with a very nice belt case for it.
Hope this helps!