Validity of Non-Compete

I have a non-compete in place with a national consulting firm. During the course of my employment I was asked to sign an additional non-compete. For doing so I was able to continue employment but not receive any additional consideration. The non-compete specifies that I am a vice-president. Since signing the non-compete I have been promoted to president of a division of the firm. I have learned that others working for the firm do not have non-competes in place. The period of non-compete is two years after termination. There is no geographic restriction on the non-compete. Certain very general consulting services are named as restricted services in the non-compete. Are any of these issues or concerns sufficient to make the non-compete invalid? Please advise.