Bought this to replace an Intel NUC 8th gen.  I've had Mac computers going back over a decade.  Was excited when I received this.  Connected it up and went through the initial setup process.  It quickly found a MacOS update (11.2) which it wanted to download.  It was about 4GB in size.  Mac Mini was connected via ethernet so I expected the download to be speedy and reliable.  It would not download the 11.2 update completely without erroring out somewhere during the download.  This is via the same ethernet cable that I've successfully and confidently used with my NUC.  So I know the cable is good.  Switching off ethernet and switching on WiFi -- success, I could download not only the 4GB MacOS update, but also the entire 12 GB MacOS Big Sur installation from the App store.  Then the next day another MacOS update was available to download.  I had hoped that the 11.2 update might include a fix for the flaky ethernet, but alas, that was not to be.  After the third attempt to download the update and it failing via ethernet, I unplugged it and boxed it back up, it's going back.  What.  A.  Lemon.