This article argues that EID and VBIED are not decisive, either in Iraq or Afghanistan. No, they're not, but they are a constant pain in the ass, and we're still losing great soldiers to the enemy because of them.
One thing this article doesn't cover is the IO component of the EID/VBIED phenomenon. The author talks about triggermen, but we also look for cameramen every time one goes off. The jihadis get a lot of mileage on their websites from footage of IED/VBIED operations against coalition forces. Whether the IO value outweighs the costs and losses incurred by the jihadis is up to someone else to determine.
Still, the article well conveys how complex the IED networks and cells are here, and how it's hard to roll up a network decisively, instead of just putting the grab on a couple of muttonheads that can be replaced in short order.