Ordered a Ruggeduino from ruggedcircuits.com a few days ago. Functions just like an Arduino Uno R3. What intrigued me was all the added protection circuitry. I'm looking to put some Arduinos into a home automation project, and the idea of connecting a bare Arduino to external relays, sensors, etc., bothers me a little bit. Generally, I'm sure a bare Arduino would work fine, but I worry about how a bare Arduino would fare after a brown out, power surge, near lightning strike, etc. The added clamping diodes and current limiters on all the Arduino inputs and outputs helps me sleep better at night.
There are a few trade offs to be aware of. The Ruggeduino parts cost more (about twice as much as a regular Arduino). In addition, the current limiters on all the I/O pins, which gives added protection, limit the output drive current to ~20mA at 0V while driving high, and only ~4-5mA at 4V. Bare Arduinos are spec'ed at 40mA per output, and I've measured ~80mA at 0V while driving high. If the reduced drive is a problem, there are holes on the board for jumpering around the current limiters. Lastly, there are 4 header pins missing - the top 2 on both sides. These are for signals no one seems to use (2 are redundant, one is a no connect), so I haven't missed them.
So far, so good. Works as advertised (just like my old Arduino Uno R3). Unlike my Arduino, the Ruggeduino did not come with Firmata pre-installed. I used the Arduino IDE to flash it in.