On our lease in Kentucky our group has passed on any buck that isn't mature for the last 5 years. The results have been crazy! In the last two years I have seen 2 booners as well as several that were mature, big whitetails. Most of the landowners have bought in to it, with about 1200 acres in the mix. I am licking my chops for next year.
On my place in Illinois we are doing the same. I only have 180 acres, and so it isn't one of those giant properties that most QDM is based upon. We cull does as much as possible, and it is strickly frowned upon by me to shoot anything less than a 2 year old unless you are a kid, new hunter, or elderly. To say that it doesn't work is a myth in my opinion. 10 years now and I have no real scientific data. Just a house full of good racks and plenty of meat in the freezer from our doe harvests. The neighbors think we are doing something funny, and I've heard rumors we bait, etc.
Even though I have a great gift of a nice piece of property in a great whitetail state, if I were to whack the first buck I see 2 things would happen: I'd be home when that big one strolls by and that little one I shot won't have a chance to grow into that big one. It's simple: shoot does when you can, pass on younger deer, and shoot a deer you are comfortable with (as long as it's 2 1/2 or older). I love it. The fun now is seeing that young 125 incher at close range, knowing I can kill him, and hoping we'll meet again in the next couple of years! I took my first big whitetail with my recurve last year. I'll never go back to wheels, and I will never quit hunting mature deer.