There are advantages and disadvantages of both - main disadvantage of a assymmetrical is not being able to run as deep as with a symetrical..tho there are ways around that ..ie by bringing the tack to the windward pontoon..
Assymetricals can go deeper as breeze increases ..I can get to 165 degrees with mine in 20knots...
The plus is they are a much nicer sail when the
wind gets tighter...