And the S9 could do around 80w/th at 10T, using Braiins OS of course, as philipma1957 demonstrated already. (I somehow lost the post where he used 475Mhz @ 7.9v ish). the J model actually even has better yield asics...

IMO, and as much as i dislike Bitmain (but at least that is cured with Braiins OS) it is the better choice here, and because its used thats money they won't get anyway.

Avalon units don't like near 40°C ish ambient temperatures, and they officially lowered their max ambient temperature to 30°C. In the same place where several Avalon units failed, the S9s are still working. If your ambient temperature is never above 30°C, you have nothing to worry about.