I'm in the same boat. I'd point out that the Medtronics basically require their CGM system to function as designed, the 670 in particular. Dunno if that would put them off-limits but I suspect the opposite: that it would be a way to get past the CGM gatekeeping by your insurer. They are pushing really hard right now to get people to sign on to the priority upgrade deal where you get a 630 to start with and then are front-listed for the 670 when it comes out. I've been told I pretty much have to decide by end of next week for them to have everything lined up with my insurance in time to get in on the deal before the Apr 28 deadline.
I've also been considering the TFlex, particularly because it's Dexcom friendly (I use the G5 even though I have a Medtronic pump) and because of their new remote-upgrade capability, which given the rate of technological change these days helps offset the problem of being committed to a device for 4 years. But also hear troubling things about J&J trying to sell off the company, and people reporting struggling with a lot of occlusions.
AND I've been considering the option @type1steve mentions: just holding off for now. I'm leery of getting the initial version of any new tech this complicated--the bleeding edge technology problem, and my current Medtronic was replaced last August, so even though my "warranty" is technically expired, the pump is actually <1yr old. I'd really like to see what the hybrid closed-loop thing is like if it works, but I also like my Dexcom and am worried that if I jump ship to the M-t system it won't be easy to revert to Dexcom insurance-wise if I find it's driving me crazy.
Dither dither dither...