Arduino Uno vs BeagleBone vs Raspberry Pi

First, the Arduino and Raspberry Pi and very inexpensive at under $40. The BeagleBone comes in at nearly the cost of three Arduino Unos. Also worthy of note is that the clock speed on the Arduino is about 40 times slower than the other two and it has 128,000 (!) times less RAM. Already, you can see the differences starting to come out. The Arduino and Raspberry Pi are inexpensive and the Raspberry Pi and BeagleBone are much more powerful. Seems like the Raspberry Pi is looking really good at this point, however, it’s never that simple. First, its price isn’t quite as good as it seems because to run the Raspberry Pi you need to supply your own SD Card which will run you another $5-10 in cost.

http://blog.makezine.com/2013/04/15/arduino-uno-vs-beaglebone-vs-raspberry-pi/