I've got 9 2012 i7 Mini Servers, 8 in my offices and one in my home office. None of my work SW is certified yet for HS - my work Minis are either on 10.11 (2) and 10.12 (6) and they're going to stay that way for awhile.
I do not have a clean install of HS on my home office Mini, but it's pretty close. It was a back up work Mac, still in the box, until several weeks ago. It sat here for a few weeks, then I updated the bottom HHD with a 512GB Samsung 850 Pro; I used a Sabrent SATA hard drive adapter (
link) that I bought at a nearby Frys for $12 to install Sierra on the Sammy SSD, then installed the SSD into a NexStar enclosure until I knew that the SSD had no issues. I installed the SSD into the Mini about a week before HS dropped, installing only a couple of apps to keep the cruft down; I still have not added additional apps beyond the Sierra install.
My advice is wait until 11.1 hits the interwebs. Finder/iTunes/Safari/Disk Utility all shipped with bugs and memory leaks - most of my work apps are not certified for HS yet, mainly due to permissions issues or incompatibility with APFS.
I have another Mac, a rMBP that I use regularly. The stock HHD is in a safe place. I have a Samsung EVO 850 in the NexStar enclosure, just in case. IMHO, HS is not ready for prime time and production machines. My 2¢.