Espressif ESP8266 is a very popular platform for IoT applications relying on WiFi, at least for hobbyists, while Espressif ESP32 is the new solution from the company that adds a CPU core, faster WiFi, Bluetooth 4.2, and various I/Os which should launch very. Amica.io released a table showing the main differences between the two processors which are expected to coexist in the market with ESP8266 used in the lower-cost segment, and ESP32 in applications requiring WiFi and Bluetooth, or some of the new interfaces.
Some of the features were clearly listed when ESP32 was first announced, but for example, I was not aware that an Ethernet MAC, and a temperature sensor were built into the new SoC. Other interesting features for the new ESP32 processor including a touch sensor, and hardware PWM both of which are missing in ESP8266. The new dual-core processor also built on existing features, as ESP32 provides more GPIO, additional software PWM channels, higher SRAM capacity, and increased ADC resolution to 12-bit.