Dexcom is the premier CGM system in the marketplace today. It's not perfect and it's not cheap but it is the standard. I use it and am quite happy with it other than the fact that with the Dexcom 6 they built in a forced expiration after 10 days of usage. This is American capitalism at its worst. They do it because they can despite their protestations that it is for clinical reasons.
That being said, they are currently recruiting for participants in the trials for the Dexcom 7. I think I am going to sign up and then let you know how things go.