http://www.policeone.com/Officer-Saf...et-you-killed/
Ron Avery has a pretty good take on this stuff (yes, I should know as I'm on the Internet).
The article makes the point that most competitions are tactically unrealistic. However, he argues that the tactically trained use competition to practice basic skills and increase speed.
Also, he brings up the idea that you need automaticity of skilled response under stress and that competition enables you to do that. Stress innoculation to avoid the freeze is a big deal now in modern views of critical incidents.
I was reading a new mystery where a big strong police detective is grabbed from the front by a big nutso who wants to kill him by twisting his neck. The guy basically freezes and doesn't employ the easiest - Glock to belly, bang, bang, bang or various combative/knife moves.
He is saved by his sidekick who is a fightin' psychologist (that really cracked me up - hahaha!). The point being the guy lacked the automaticity under stress.
Glenn - a rather laid back FOG psychologist.