Here's my two cents.
I use both. I started (Dexcom) CGM about a month before I started using the OmniPod pump. As soon as I saw the demonstration of GCM, I knew that it was for me. I primarily use CGM to warn me when my BG is low because I am hypoglycemic unaware. I am usually in the 40s or 50s before I realize something is wrong.
Before I started the OmniPod pump, I was very out of control (A1C 9-11). I think it was a combination of bad carb counting and my long-acting insulin not covering my basal needs.
Why use CGM?
- Alerts (low, high, fall, rise) that vibrate and beep. This lets me and my family sleep at night knowing that if I go low, the alert will wake me up so I can treat it and wake up in the morning.
- Identifying BG fluctuations between meals, especially when sleeping. There are posts on this forum that talk about finding out that the poster had hypoglycemia overnight. The numbers before bed and at waking up were fine, but in between there was hypoglycemia.
- Identifying what the affect of certain foods are on BG. It is very helpful to see for example, what a slice of pizza or some Chicken and Broccoli does to your BG. I determined that I need to program my OmniPod pump to give my bolus for Chicken and Broccoli over 2 - 3 hours. Otherwise the insulin kicks in before the food and I go hypoglycemic. I treat the hypoglycemia, and then the food kicks in and I go hyperglycemic.
I use the tests from the PDM to calibrate the Dexcom CGM. I have the Seven Plus model and it is "open", meaning that I can use any glucometer to calibrate. I think a prior Dexcom model required calibration with a specific glucometer, but that is no longer the case.
Regarding the difficulty of getting used to, I would suggest that you do not start using both devices at the same time. Also, with your OmniPod, expect some highs and lows until you and your medical team determine the correct settings for the pump. It usually takes a while to determine the correct ratios.