...There were many people on this very thread that wrote "do not buy the first few batches of the s9. They will have problems just like the S5 and s3 did". And I did not buy until batch 5. Which must be the reason why I am not having any problems. So it sounds like other people did not use the same wisdom.
Like I said, I'm not saying that they are without issues (I have some from batch 4 that run ~10 rather than ~13, but I'm "OK" with it because the ROI on downtime and shipping would take 27 months to equalize).
I'm simply saying that you have to be completely unconcerned with ROI, or just a complete fanboy, to say that the 2 rigs (S9 and A7) are even in the same market for comparison.