Mac vs HaC
Below is a comprehensive comparsion between the various 2018 Mac minis and the two Hades Canyon NUCs. The source for most data are linked in the first row, otherwise it is linked in the individual cell.
General buying advice for Mac mini is if you require high CPU performance and do not care about GPU performance, if you need extra TB3 ports, or if you need the lightest and most power efficient computer (per litere). You should get a Hades Canyon NUC if you need any GPU performance, value extendibility, or require many more ports than what the Mac mini has to offer.
*NUC kits typically do not come with RAM/SSD unless as part of some bundle deal.
**Mac mini can be configured for 10Gb Ethernet for $100 extra.
****Apple products rarely sell under MSRP while NUCs can often be found on sale for as much as 20% off.