Without a doubt, I can agree with you that MiniMed CGMs absolutely suck and that the "artificial pancreas" marketing from MiniMed is crap. I used the MiniMed CGM on my pump for about 2 years and it was often way off my actual blood sugar. I talked with MiniMed reps several times and they would tell me the same crap: don't calibrate when your blood sugar is rising / dropping, don't calibrate more often than every 8 hours, etc., etc. I stuck with it mainly because of the convenience factor of having only one device to carry around.
My doctor convinced me to try a Dexcom because of the issues I was having, and I can tell you that it's a world of difference. The Dexcom has been so damn accurate, and a hell of a lot more comfortable than any of the MiniMed CGMs I have used. I can let it run past calibration (>12 hours) and it still gives readings. When I go to calibrate it (even if it's been >12 hours) it's very rarely off by more than 20 mg/dL unless my blood sugar is shooting up like crazy.
Maybe you have tried it, and maybe it didn't work for you.. but don't write off all CGMs. They do work. The only thing that sort of sucks is having to carry around another device.. For what it's worth, last time I saw the study in TFA, they were using a Dexcom CGM.