Arduino has been inspiring lots of projects. So, this one, so called netduino, seems interesting as it is .Net Micro Framework based development board and is open source as well. This means you can program it by using .NNET programming technology that include lots of features like multithreading, event based programming, debugging and more. Board includes a 32 bit Atmel ARM7 microcontroller with 128KB Flash and 30KB RAM.
It has a list of features that are far ahead comparing to regular Arduino. So if you need more power to perform more complex applications consider using this one. And yes – it is compatible to standard Arduino shields.