RE: Extra vs Edge
The Edge has a straight leading edge which makes it more willing to yaw from side to side.
In 3D this is good. IN IMAC it's not so good, but at the lower levels probably makes only a little difference.
Extras, Sukhois, etc. have a swept leading edge that is less willing to Yaw. The Giles is even more swept and has a very straight line feel to it.
TF