Until you have stood your ground against someone who is not "holding back", who is of equal skill and determination and who does not have your comfort and best interests at heart how would you ever know if the thing that you have been training for (sometimes for decades) is of ANY value?
This is a fairly interesting discussion the merits of competition, but I wonder if the above quote is about competition. My understanding is that there are rules in competition...even unwritten ones as in ultimate fighting...so that practitioners can come out and fight again another day.
The above quote, seems to me, to be valid insofar as "testing your Aikido". Go to an area where you are sure to be attacked and then test your aikido. or yourself.
I think competition is a place where you get better at competition. It also might help improve your Aikido, but it certainly isn't the only way. I also really don't think its about no holds barred fighting.
The various styles that put different emphasis on different aspects of training make an interesting combination of focuses and teaching/learning/training methods. My own style does not have a competition where two are fighting each other. The competition that does exist is kata competition and jiyuwaza competition where the purest in form wins. Sort of like pairs figure skating. My style focuses on balance, timing, body mechanics and the form of the technique. "With form comes power" or "Power comes from form" or thoughts like that justify the training (and seem to have proven themselves in some results I have seen).
Isn't there a story out there about Ueshiba Sensei not wanting to demonstrate Aikido to the Emporer because to be true to the Emporer and to Aikido his uke would have to die at the beginning of the 40 minute demo? Aren't there also stories about top teachers going out and challenging people in the street to see how good they were? These stories aren't about competition...but they are about testing oneself.
Anyway...I don't know very much about competition in Aikido. But I think I'll consider it another training method after reading this thread.