Raspberry Pi vs Arduino
Raspberry-Pi and Arduino devices both serve more or less the same purpose. They are great for micro-controller based automation systems. They have similarities and differences and the choice of micro-controller whether Arduino, Pi or BeagleBone depends on the requirements of projects you are working on.
These alternative microcontrollers have been user tested and they are among the best alternatives available right now
Raspberry Pi v/s Arduino
Netduino Plus1 is open source platform with a 32-bits controller
Much affordable single-board computer, BeagleBone Black DevKit is suitable for all types of projects.
Faster than Pi