Ok, how about this for a definition:

"Insurgency is a condition where a government's legitimacy among a distinct population of the governed declines to the point where that population organizes and is willing to use violence against the government. Insurgency is differentiated from other forms of internal conflict by the strategy insurgents use, which is driven by the insurgent's inability to openly challenge the government. Insurgent strategy utilizes subversion, limited violence and political action."

So here's the idea, very simplistically:

- Strong government / weak opposition = insurgency
- Government and opposition roughly equal in terms of power = civil war
- Weak government / strong opposition = coup or a quick revolution/revolt.

In essence, I think Steve Metz and Col. Jones are both right, or at least their definitions don't have to be incompatible.