Where are these ratings found? Is this "green light" from Consumer Reports or some similar magazine?
The ratings are found right here on MacRumors:
https://buyersguide.macrumors.com//#Mac
They are a suggestion as to where a device is in its product cycle.
Green means recently updated. It is unlikely to be superseded by something more modern any time soon….. Hence buy with confidence that you'll have the latest for a while to come.
Yellow means mid-cycle. Newer tech is in the offing, but a newer version of the device is still far from imminent…… Hence, buy if the device fits your needs, and you are not bothered about having to have the latest gear.
Red means update needed or on the way. Updated versions of the device sporting the latest tech will be / should be available soon…… Hence, wait a bit if you can, and you will take delivery of a state of the art device……
But be careful what you wish for!
The 2014 Mini is the most recently updated machine in the Mac line-up, but that came about a couple of years after the previous update, late 2012. Anticipated with much excitement, the 2014 Mac Mini proved to underwhelming to many.
The latest Mini comes with more modern connectivity and lower power consumption. However, there has been only a slight increase in performance for the duo core models, and the quad core model was dropped. It now comes with a choice of 4, 8 or 16 GB of RAM, but without the option of installing more RAM after purchase.