Feather seems like a great choice for boards of this class.
From the Arduino Uno R4 FAQ…
> “the Arduino UNO R4 WiFi was specifically designed to ensure compatibility with previous shields and compatible hardware developed for the Arduino UNO R3. The UNO R4 WiFi maintains the same mechanical and electrical compatibility, allowing you to seamlessly use your existing shields and hardware with the new board. This makes it easy to upgrade to the UNO R4 WiFi without the need for significant changes or adaptations to your projects.”
In addition to physical compatibility, maintaining the GPIO pin layout means software libraries created for earlier Arduinos should continue to work. For example, an interface library for a sensor or actuator that’s reused project to project.
From the Arduino Uno R4 FAQ…
> “the Arduino UNO R4 WiFi was specifically designed to ensure compatibility with previous shields and compatible hardware developed for the Arduino UNO R3. The UNO R4 WiFi maintains the same mechanical and electrical compatibility, allowing you to seamlessly use your existing shields and hardware with the new board. This makes it easy to upgrade to the UNO R4 WiFi without the need for significant changes or adaptations to your projects.”
In addition to physical compatibility, maintaining the GPIO pin layout means software libraries created for earlier Arduinos should continue to work. For example, an interface library for a sensor or actuator that’s reused project to project.