Esp32 is just as big if not bigger.

ESPs are great, but their hobbyist ecosystem ultimately relies on the goodwill of a Chinese company that could just as easily decide they want to go the way of Qualcomm, or worse.

And a dev board only costs a couple of dollars on AliExpress.

Espressif has a pretty good Arduino compatibility layer for the ESP32 series. So you can follow Arduino tutorials and almost everything will "just work". This what I use for quick and dirty projects.

For more "serious" things, you have the ESP-IDF, which is a pretty good C-style interface to all sorts of hardware features. Less newbie friendly than the Arduino interface, but gives you more control. And it can be used in combination with the Arduino interface.

And then, as the cherry on top, you have their official Rust HAL for the ESP chips, implementing the standard Rust embedded-hal interfaces so it should "just work" with the growing Rust embedded ecosystem.

It's honestly impressive. The only thing that has kept Arduino competitive is their brand, good reputation, and focus on the education and tinkerer space. I frankly don't understand what value Qualcomm sees in Arduino if they're just gonna throw away that reputation and education friendliness.

I wish there was a esp32 board with optically isolated 24v level shifters and screw terminals…