Today I got the new Arduino Uno R4 boards in the mail. This includes the Minima and Wifi models, but this post will just concern itself with the Minima.
The R4 Minima is much less expensive than the R3, but still a bit more than a good R3 clone like the Elegoo. You can see from the photo that the R4 is a much cleaner design. It uses a USB-C connector instead of the antiquated USB-B. It’s a 5 volt board and has the (presumably) same pins. But it uses a more modern microcontroller from Renesas. There is far more memory, which makes it a much better candidate to run FreeRTOS on. It also has hardware single precision floating point.
But the different architecture is where potential problems are. If you use only Arduino libraries and don’t access the “bare metal” of the microcontroller you will do fine. But the architecture is completely different and far more complex than that ATmega328P in the Uno R3.
This doesn’t bother me much. However having to be compatible means that the device is dumbed down — fewer features, slower operation, and less precision than is capable by the part. This is the same issue with the SAMD-based Arduinos and the ATmega4809-based Arduinos. But in this case they can more likely get away with it as just the next generation of the Uno.
I’m still busy on the SAMD, so it will be a few months before I can really investigate this part. But I can recommend it as a Uno R3 replacement for basic users (experimenters starting out or classroom use).