For those curious about Mojave but just not sure yet. You can do what I did.…
A clean install of Mojave easily fits on a 64-128GB USB Stick / SD card, etc. with room left over for some test documents. So you can dual boot your current MacOS and Mojave 10.14.1 while you try it out. If Mojave looks good, start installing critical apps and testing them. If Mojave still looks good, you can continue building out your clean install of Mojave or upgrade your current startup drive to Mojave.
FWIW we went from El Capitan 10.11.6 to Mojave 10.4.1 on a late 2014 Mini and a late 2013 iMac 27” with no serious drama. I started with a clean install of Mojave 10.14.1 on a 128GB Micro SD card. Installed all of our 3rd party software. After testing it on both Macs, we simply kept booting Mojave on the Micro SD cards. Kind of a poor boy's SSD for older Macs with spinners inside
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