I have used the shaggie headgear with a camo boonie hat and the whitetails didn't get spooked. They would do their thing like I wasn't there. This was during my first year hunting in upstate NY.
I did not have the full shaggie set, just the face mask. I was on a budget so I wore black pants and a green jacket, both in fleece. I once read on Tradgang that covering the head/shoulder outline and hands are more important than covering the whole body in camo. I am convinced that this is true with my non-camo fleece and basic headgear and gloves, at least for deer.
I like the shaggie face mask, but the full suits seems awfully bulky and I would be concerned about it absorbing water. Burlap seems even worse, and the ghillie suits I have seen are extremely heavy.
For turkey season this year I bought myself a complete 3D mesh ASAT camo set. Its awesome. I mainly got the ASAT since birds are supposed to see in color and supposedly also see parts of the UV spectrum. ASAT does not use any UV dyes and the mesh suit fits over whatever I want to wear underneath, camo or not. Longpants when its cool, or shorts when its hot. Just one set of camo makes it easy on the budget.
I really think the mesh suits are the way to go. I now live in Oregon and bow season is like hunting in Hades. Anyway, while I was turkey hunting this month I came across a doe that stared and stared at me. She must have watched me walk down the hillside she was standing on. By the time I noticed her, she was shaking her head back and forth like a dog. It was really funny, like she was trying to figure out what the heck I was. I then noticed the doe was with 3 other does and I walked closer to them and stopped at about 25 yards away. They just continued to browse and did not seem to care that I was there. I did not move slowly either. I was actually a bit nervous since I was trying to find my truck and a storm was coming.
Even though it wasn't deer season and they weren't being hunted, I was impressed. The fact that the deer didn't run away as I stomped down the hillside made me feel a little more confident in the camo since I'm not usually the camo type.
I would suggest the mesh style of camo suit, not just the ASAT, but any brand. I think the ghillie makes sense for a sniper, but it might be overkill for deer. Just my opinion.
Sorry for the long post, but I thought I would share my experience.