The MEGA 2560 is designed for more complex projects. With 54 digital I/O pins, 16 analog inputs and a larger space for your sketch it is the recommended board for 3D printers and robotics projects. This gives your projects plenty of room and opportunities.
The Raspberry Pi 2 is the second generation of the Raspberry Pi . It packs 4 times the power and double the RAM. The Raspberry Pi 2 is capable of running windows 10, and snappy Ubuntu coreThis Product is Retired, Check Raspberry Pi 3 Here