My 2 cents:

I know several people who have had good luck with "fresh earth" spray. If it works, great, but I'm a little skeptical about ANY so-called cover scent.
First, just because it smells like dirt to me(or pine,coon urine,etc) doesn't mean it smells that way to deer. I'm afraid the deer might smell it and recognize it as foreign and become spooked or become overly cautious. Second, if a deer can smell your cover scent, it can smell you. I really don't believe that cover scent really "covers" anyhow. At least for the most part. I do believe some "odor-eliminators" do help, but human scent is present and produced by every square inch of your body. I think in most cases the deer will smell "earth and human" mixed together.
Another something often overlooked by hunters is breath. I get my teeth cleaned every year before deer season and take full measures to have a clean mouth before entering the woods. Your mouth is one of the biggest human scent factories in existence. Brush, floss, listerine, and I often chew some dentyne ice on the way to my hunting area(I spit it out before I actually go in the woods, but I'm convinced it helps get breath under control a little better than just brushing and rinsing.)

So to answer your question, I think there's some things that can help, but nothing beats being as clean as you possibly can, being up high in a tree, and playing the wind. I decided years ago not to use any cover scents, lures, etc, and I can honestly say I've spooked less deer than I did when I used that other stuff. My vote is for "scent free", although I think it would be best described as "as scent free as possible and playing the wind".
GOOD LUCK!!