I have the Mi stick and it keeps rebooting. I've read a lot of people have the same issue, but I don't know if this is specific to the stick for whatever reason or if the box would have the same issue. Maybe it's power related that the box wouldn't face?
What country are you in? The Mi Box S runs cooler and doesn't really have these issue.
If you are in North America, grab the Onn 4K Box (Wal-Mart has it sometimes for $20-$30). It runs AndroidTV 10, doesn't have any of the bugs from A11 that the shield has gone through.
So you have a few options. Even the TiVo 4k is decent if you can't find anything else.