As the others have said, expo makes it easier to be accurate in the middle of the throws (for landing etc) because the middle is less sensitive, but beware of one thing...

If you are flying inverted and have to have a small amount of 'down' to keep it level (quite common) don't forget the area you may now be in to control the plane may be in a faster reacting (more sensitive) area of the curve and this will make flying inverted more difficult if you have too high an expo dialed in.

-David C.