The Arduino ADK is a microcontroller board based on the ATmega2560. It has a USB host interface to connect with Android based phones.
The STM32 Nucleo-64 boards provide an affordable and flexible way for users to try out new concepts and build prototypes with the STM32 microcontrollers, choosing from various combinations of performance, power consumption and features.
This is FS1000A 433mHz Tx RF Radio Module. This RF module comprises of an RF Transmitter and an RF Receiver. The transmitter/receiver (Tx/Rx) pair operates at a frequency of 433 MHz. An RF transmitter receives serial data and transmits it wirelessly through RF through its antenna connected at pin4.
Now with this low cost version of Mega compatible with CH340 (USB to UART chip), you have more reasons to get this board instead of UNO :). And Mega compatible board is fully compatible with Arduino Mega2560 R3,