Seeeduino V4.2 is an Arduino-compatible board, which is based on Atemga328P MCU. There are so many Arduinos and Arduino-compatible boards in the world, and the Seeeduino V4.2 is one of the best Arduinos, Seeeduino V4.2 is generally more stable, easy-to-use and it's even good looking. Seeeduino V4.2 is based the Arduino UNO bootloader, and with an ATmega16u2 as a UART-to-USB converter, which means that the board ca basically work like a FTDI chip. You can program the board via a microUSB cable. Also, you can power the board using a DC Jack with 7V to 15V is acceptable. There's a switch to choose the system supply voltage, 3.3V or 5V, which is very useful if you want to set the system to 3.3V to save power.
Features
ATmega328 microcontroller
Arduino UNO bootloader
14 Digital I/O Pins (6 PWM outputs)
6 Analog Inputs
ISP Header
Arduino UNO-R3 Shield Compatible
microUSB programming and power supply
3 on-board Grove connectors
3.3/5V system operation power switch
DC Current per I/O Pin 40 mA
DC Jack Input 7v-12v
Flash Memory 32 KB
RAM 2 KB
EEPROM 1 KB
Clock Speed 16 MHz
Note
Operating the chip at 16 MHz with 3.3 volts is beyond the specified maximum frequency "Safe Operating Area" for the ATmga328P chip. So when you switch the working voltage to 3.3V, it may not be safe. However, at room temperature, most chips work fine that way.
The Arduino Leonardo is a microcontroller board based on the ATmega32u4. It has 20 digital input/output pins (of which 7 can be used as PWM outputs and 12 as analog inputs).
Seeeduino Lotus is an ATmega328 Microcontroller development board. It is a combination of Seeeduino and Base Shield. It uses Atmel ATMEGA328P-MU and CP2102N. ATMEGA328P-MU is a high performance, low power 8-Bit AVR Microcontroller.