I have, or rather my doctor has. To date, Medicare doesn't cover them. Having had a lot to do with metrology in my career, I would certainly get one if I could afford it.
There's definitely a learning curve to managing the condition, balancing food intake vs. insulin dosage. I've been doing it for years now, and I'm holding my a1C in the low 6's, but it took a while. Continuous measurement would help a new sufferer a lot in climbing that curve.
I view it as being no different than the industrial process control that was a large part of my career. It's a fundamental principle there that more frequently you measure the better your control will be.
And type 1?
I sincerely hope that the price will come down on these devices so you can obtain one.