I have a 2012 2.6ghz quad-core i7 Mini with 16gb RAM and original Apple 256gb SSD. It is still a nice machine and I plan to keep it for awhile. The HD-4000 graphics chip on the 2012 Mini is arguably its biggest weakness, and will limit the kinds of displays that you use and be somewhat limiting with demanding graphics software.
I also have a 2014 2.8ghz dual-core i5 Mini with 8gb RAM and original Apple 128gb SSD (which I split from the fusion drive) - this machine is one step up from what the OP has purchased. Mine is just a media server and it works very nicely for that. In terms of CPU performance, it's much slower than my 2012 quad. But it has the Iris 5100 graphics chip which is more modern.
I think the 2014 Mini that you bought should be fine for general usage if you install a SSD, and $250 sounds like a decent price. I'm running Mojave on mine with no problems.
plus on the 2012 one can install 2 SSD's to give blistering speeds if required at sensible prices
This might be a bit misleading. The 2012 quad-core Mini's (there were two models - 2.3ghz and 2.6 ghz) have about 50% better CPU performance than the best 2014 Mini, so that's great if you're doing things like rendering video. But the base model 2012 Mini only has a dual core CPU and will be slower than the Mini that the OP bought. I had one of these too, and it was fine, but I wouldn't recommend one today. So, it depends on
which 2012 Mini you're talking about.
Regarding "blistering speed", the 2014 Mini beats the 2012 hands-down when it comes to SSD speed. Here's what I get from the original Apple SSD on my 2012 Mini.
This how the original SSD performs on my 2014 Mini. You can see that it's quite a bit faster because it has a faster interface than the 2012.
Now, I would not fixate on this too much, an average user might not notice much difference. But the 2014 Mini definitely wins the SSD speed contest.
