That SAM microcontroller is interesting. The 32-bit ARM core is basically oriented toward computer use and not controller use, so the instruction set isn’t really quite right for the job. Frankly the whole chip is overly complicated. Some years ago I used a 32-bit ARM core microcontroller from another vendor on the job. I’m not convinced that for controller use it has much of an advantage over the AVR architecture, which was developed specifically for controller applications.
It does seem to have a benefit in cost, and the availability of extra RAM/ROM capacity. As I develop the next book I’ll have a better idea of the performance difference. It certainly looks like the Arduino best buy boards are the Nano Every (with a modern AVR microcontroller) and the Nano 33 IoT (with the SAM and a Bluetooth/WiFi radio). I would think twice about buying any other Arduino boards, although there are of course very inexpensive clone boards of the plain Nano and the Micro that are very cost effective if you don’t mind their cheaper construction.
So in the coming weeks I’ll try to get something down on virtual paper (I use Scrivener) beyond figuring out how I want things organized. I’ve already created a cover. Anything other than “real work” I guess! Book sales are gradually going up which gives me some impetus to write. The chances are increasing that people will actually be interested in buying what I write.