Interesting question. Not a simple yes or no though. We have no idea what it has yielded, it hasn't been long enough.
Basically in history the full effects of events are not fully understood until several decades later. The reason is simple. Everything is interconnected. What could be yielded from Iraq might have changed the course of action of something that might lead to something else later? At any rate our military occupation has certainly taught the US military and Intelligence community some new tricks that we might use later. That might be it...or maybe a pro-US state might emerge in Iraq. Perhaps an understanding of Arabic cultures might be an advantage later on for the United States? Who knows? I mean there is no end to the possibilities of things that could have come out of Iraq. We won't know if they were worth it till we get to spend those intangible things.
Or maybe it was a totally worthless venture?
At any rate I won't be hardlining an opinion of this war until I find out what came out of it...on my 60th or 70th birthday.