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It really depends on and which movements you compare.
There used to be a big gap in quality control between ETA and Mioyta, but even then it wasn't a problem if the movement was "serviced" by somebody who knew what they are talking about. I'm talking bits of swarf inside...
In my view, the low grades of ETA and Miyota are pretty much equal now days. I've never noticed a difference between a well installed Mioyta and a base ETA on my timegrapher. I hear that QC has increased a lot with Mioyta recently also.
As long as the price is right, if it keeps good time and is reliable, that's good enough for me.
Apart from the rotor noise, is there much difference? I'm not a movement connoisseur, but I thought both the Mitoya and the ETA were time-tested workhorses that were much of a muchness.