RE: Ghillie Or No Ghillie!
I haven't used one but my hunting buddy took his home made one out dove hunting (cuz he was hunting close to a subdivision and didn't want to stand out) and had a group of white tails walk by. He played with them for about 10 minutes getting them to come into him and then backing off. He could tell that they couldn't tell what he was and were trying to figure him out. He finally had to yell and drive them off because they were getting too close (w/in 10 ft) and he was afraid the buckmight get aggressive if he actually winded him.
I guess I'd say use it when you think you need it.
Spud