Hey Stephen,
I still actually use AutoCad on most plans I make simply because I can lay things out quicker, then import the linework into Dynascape. Personally I dont like how some of the editing tools work in Dynascape but the program is good with making nice looking planting plans that can be colored really quick in Dynascape Color.
Since the office already had dynascape I have done my best to learn it, I am curious how Landfx compares now.
Hope that helps,
cheers