I have flown the 747 in virtually the entire allowable CG range. Handling is not noticeably different throughout the range. The only exception seems to be the Classic during autoland, where a forward CG tends to cause the airplane to overtrim nose-up.
Also, I tend to be wary of Takeoff trim settings that are outside the "usual" range. It's nice when the loadmaster alerts me ahead of time that he's loading near the fwd or aft limit...