I like the open patterns as well. I had a similar experience to yours.
Several years ago was hunting with my brother and my cousin. Cousin was younger, in high school and had no money. My bro and I were sporting our new MO break up outfits and cousin in his BDU's in woodland that he got from an army surplus store.
I had put the stands up and we were walking in. Sent my brother off to his stand and watching him walk away noticed the same thing you did. After about 25 yards he looked like a black bear walking through the woods. The camo was doing no good could see his outline perfectly. My cousin heads in next, I watch him in the el cheapo suit and he virtually disappears the farther he gets from me. I looked away for a few seconds and then, if not for his movement I woudn't have been able to find him, and I knew where he was.
That sealed it for me. I was amazed, though I shouldn't have been. I buy BDU style clothes now in the woodland pattern and in desert for when out on the prarie. I also have some Nat Gear and that seems to work well also. I don't think it is as effective as the military patterns. When you think abou it, one group is doing everything they can to save human lives, the other is pushing a million dollar marketing campaign to sell as many clothes as possible. There is a reason the military sticks with those basic, open, outdated patterns.