Made especially for robotic uses, has power buses near the signal pins, so plugging sensors just got easy. All of the PWM pins have neighboring unregulated power for direct use with servos. Also I2C pull-up resistors may be installed if needed. The UART pins also go to a 3 pin header for TTL serial if needed. Check it out here:
http://www.curiousinventor.com/kits/roboduino
For Robotics, if Roboduino could be as better as Axon, that will be great.
The Axon was developed for robots that go beyond the basics. With the Axon, you will no longer need to worry about not having enough I/O as it has 55+ for you to use - up to 16 ports for analog sensors, and up to 18 for interrupts. You will never be wanting of UART, as there are 3 directly available, with a 4th used for a USB connection directly to your PC. No additional programmer needed due to a built in programmer (bootloader).
However I like to use Arduino software. How to use Arduino with Axon?
or how to design a Arduino board like Axon board?
Did I mention Roboduio is compatible with the shields? Yes, just use female headers on the shield and plug it on the Roboduino!
The Roboduino is 100% Compatible with the Arduino software.
Many cool robots have already been built with the Roboduino as the brains .
Even a self-balancing bot has been built 
What about making a RobotDruino small board (Bare Bones) with the Atmega328 a L293D and a I2C small EEROM?
That will be very very cool 