Sorry, had it in my head for some reason. Blame the Christmas eggnog

On the flip side there is a wealth of information around on Arduino.
It really comes down to what the requirements are.
A learning exercise is one thing. If thats the case then a raspberry pi is also a good platform though not so strong in the robot control area yet

I've spent alot of time reading the posts on the Arduino forum (blame the Christmas telly)

I do recommend http://rcarduino.blogspot.co.uk/

There are also tutorials on youtube

The platform has limitations. There are typically only a couple of hardware interrupt pins and the code examples I've seen are single threaded. Some interesting posts

http://arduino.cc/forum/index.php/topic,105573.0.html

http://arduino.cc/forum/index.php/topic,50539.0.html

http://arduino.cc/forum/index.php/topic,60508.0.html


Most of the fighting robot applications I have thought of are achievable with some simple analogue electronics and at worst a PIC. Horses for course really. If someone is beating your bot or trying to catapult it through the air keeping it simple is important